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<span>Systems of units</span> </div> </a> <button aria-controls="toc-Systems_of_units-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Systems of units subsection</span> </button> <ul id="toc-Systems_of_units-sublist" class="vector-toc-list"> <li id="toc-Traditional_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Traditional_systems"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Traditional systems</span> </div> </a> <ul id="toc-Traditional_systems-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Metric_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Metric_systems"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Metric systems</span> </div> </a> <ul id="toc-Metric_systems-sublist" class="vector-toc-list"> </ul> 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comparison to familiar concepts</span> </div> </a> <ul id="toc-Informal_comparison_to_familiar_concepts-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Base_and_derived_units" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Base_and_derived_units"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Base and derived units</span> </div> </a> <ul id="toc-Base_and_derived_units-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Physical_quantity_components" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Physical_quantity_components"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Physical quantity components</span> </div> </a> <ul id="toc-Physical_quantity_components-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Dimensional_homogeneity" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Dimensional_homogeneity"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Dimensional homogeneity</span> </div> </a> <ul id="toc-Dimensional_homogeneity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Converting_units_of_measurement" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Converting_units_of_measurement"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Converting units of measurement</span> </div> </a> <ul id="toc-Converting_units_of_measurement-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Real-world_implications" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Real-world_implications"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Real-world implications</span> </div> </a> <ul id="toc-Real-world_implications-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span 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Available in 96 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-96" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">96 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%88%D8%AD%D8%AF%D8%A9_%D9%82%D9%8A%D8%A7%D8%B3" title="وحدة قياس – Arabic" lang="ar" hreflang="ar" data-title="وحدة قياس" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Unidat_de_mesura" title="Unidat de mesura – Aragonese" lang="an" hreflang="an" data-title="Unidat de mesura" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Unid%C3%A1_de_midida" title="Unidá de midida – Asturian" lang="ast" hreflang="ast" data-title="Unidá de midida" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-av mw-list-item"><a href="https://av.wikipedia.org/wiki/%D0%91%D0%BE%D1%80%D1%86%D0%B8%D0%BD%D0%B0%D0%BB%D1%8A%D1%83%D0%BB_%D1%80%D0%B8%D0%BA%D3%80%D0%BA%D3%80%D0%BA%D0%B5%D0%BD" title="Борциналъул рикӀкӀкен – Avaric" lang="av" hreflang="av" data-title="Борциналъул рикӀкӀкен" data-language-autonym="Авар" data-language-local-name="Avaric" class="interlanguage-link-target"><span>Авар</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/%C3%96l%C3%A7%C3%BC_vahidl%C9%99ri" title="Ölçü vahidləri – Azerbaijani" lang="az" hreflang="az" data-title="Ölçü vahidləri" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%AA%E0%A6%B0%E0%A6%BF%E0%A6%AE%E0%A6%BE%E0%A6%AA%E0%A7%87%E0%A6%B0_%E0%A6%8F%E0%A6%95%E0%A6%95" title="পরিমাপের একক – Bangla" lang="bn" hreflang="bn" data-title="পরিমাপের একক" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%90%D0%B4%D0%B7%D1%96%D0%BD%D0%BA%D0%B0_%D0%B2%D1%8B%D0%BC%D1%8F%D1%80%D1%8D%D0%BD%D0%BD%D1%8F" title="Адзінка вымярэння – Belarusian" lang="be" hreflang="be" data-title="Адзінка вымярэння" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%90%D0%B4%D0%B7%D1%96%D0%BD%D0%BA%D1%96_%D0%B2%D1%8B%D0%BC%D1%8F%D1%80%D1%8D%D0%BD%D1%8C%D0%BD%D1%8F" title="Адзінкі вымярэньня – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Адзінкі вымярэньня" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A1%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B8_%D0%B5%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D0%B8" title="Системи единици – Bulgarian" lang="bg" hreflang="bg" data-title="Системи единици" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Mjerna_jedinica" title="Mjerna jedinica – Bosnian" lang="bs" hreflang="bs" data-title="Mjerna jedinica" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Unitat_de_mesura" title="Unitat de mesura – Catalan" lang="ca" hreflang="ca" data-title="Unitat de mesura" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%A4%D0%B8%D0%B7%D0%B8%D0%BA%C4%83%D0%BB%D0%BB%D0%B0_%D0%BA%D0%B0%D0%BF_%D0%BF%C4%95%D1%80%D1%87%D0%B8" title="Физикăлла кап пĕрчи – Chuvash" lang="cv" hreflang="cv" data-title="Физикăлла кап пĕрчи" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Fyzik%C3%A1ln%C3%AD_jednotka" title="Fyzikální jednotka – Czech" lang="cs" hreflang="cs" data-title="Fyzikální jednotka" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-sn mw-list-item"><a href="https://sn.wikipedia.org/wiki/Chiyero_chekupimisa" title="Chiyero chekupimisa – Shona" lang="sn" hreflang="sn" data-title="Chiyero chekupimisa" data-language-autonym="ChiShona" data-language-local-name="Shona" class="interlanguage-link-target"><span>ChiShona</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/M%C3%A5leenhed" title="Måleenhed – Danish" lang="da" hreflang="da" data-title="Måleenhed" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/%D8%B9%D8%A8%D8%B1%D8%A9" title="عبرة – Moroccan Arabic" lang="ary" hreflang="ary" data-title="عبرة" data-language-autonym="الدارجة" data-language-local-name="Moroccan Arabic" class="interlanguage-link-target"><span>الدارجة</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Ma%C3%9Feinheit" title="Maßeinheit – German" lang="de" hreflang="de" data-title="Maßeinheit" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/M%C3%B5%C3%B5t%C3%BChik" title="Mõõtühik – Estonian" lang="et" hreflang="et" data-title="Mõõtühik" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%9C%CE%BF%CE%BD%CE%AC%CE%B4%CE%B1_%CE%BC%CE%AD%CF%84%CF%81%CE%B7%CF%83%CE%B7%CF%82" title="Μονάδα μέτρησης – Greek" lang="el" hreflang="el" data-title="Μονάδα μέτρησης" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Unidad_de_medida" title="Unidad de medida – Spanish" lang="es" hreflang="es" data-title="Unidad de medida" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Mezurunuo" title="Mezurunuo – Esperanto" lang="eo" hreflang="eo" data-title="Mezurunuo" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-ext mw-list-item"><a href="https://ext.wikipedia.org/wiki/Mid%C3%ADa" title="Midía – Extremaduran" lang="ext" hreflang="ext" data-title="Midía" data-language-autonym="Estremeñu" data-language-local-name="Extremaduran" class="interlanguage-link-target"><span>Estremeñu</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Neurri-unitate" title="Neurri-unitate – Basque" lang="eu" hreflang="eu" data-title="Neurri-unitate" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%DB%8C%DA%A9%D8%A7" title="یکا – Persian" lang="fa" hreflang="fa" data-title="یکا" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Unit%C3%A9_de_mesure" title="Unité de mesure – French" lang="fr" hreflang="fr" data-title="Unité de mesure" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Aonad_tomhais" title="Aonad tomhais – Irish" lang="ga" hreflang="ga" data-title="Aonad tomhais" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Unidade_de_medida" title="Unidade de medida – Galician" lang="gl" hreflang="gl" data-title="Unidade de medida" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%8F%E0%AA%95%E0%AA%AE" title="એકમ – Gujarati" lang="gu" hreflang="gu" data-title="એકમ" data-language-autonym="ગુજરાતી" data-language-local-name="Gujarati" class="interlanguage-link-target"><span>ગુજરાતી</span></a></li><li class="interlanguage-link interwiki-hak mw-list-item"><a href="https://hak.wikipedia.org/wiki/T%C3%A2n-vi" title="Tân-vi – Hakka Chinese" lang="hak" hreflang="hak" data-title="Tân-vi" data-language-autonym="客家語 / Hak-kâ-ngî" data-language-local-name="Hakka Chinese" class="interlanguage-link-target"><span>客家語 / Hak-kâ-ngî</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%B8%A1%EC%A0%95_%EB%8B%A8%EC%9C%84" title="측정 단위 – Korean" lang="ko" hreflang="ko" data-title="측정 단위" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%89%D5%A1%D6%83%D5%B4%D5%A1%D5%B6_%D5%B4%D5%AB%D5%A1%D5%BE%D5%B8%D6%80%D5%B6%D5%A5%D6%80" title="Չափման միավորներ – Armenian" lang="hy" hreflang="hy" data-title="Չափման միավորներ" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AE%E0%A4%BE%E0%A4%AA%E0%A4%A8_%E0%A4%95%E0%A5%87_%E0%A4%AE%E0%A4%BE%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%95" title="मापन के मात्रक – Hindi" lang="hi" hreflang="hi" data-title="मापन के मात्रक" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Mjerna_jedinica" title="Mjerna jedinica – Croatian" lang="hr" hreflang="hr" data-title="Mjerna jedinica" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Satuan" title="Satuan – Indonesian" lang="id" hreflang="id" data-title="Satuan" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Unitate_de_mesura" title="Unitate de mesura – Interlingua" lang="ia" hreflang="ia" data-title="Unitate de mesura" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/M%C3%A6lieining" title="Mælieining – Icelandic" lang="is" hreflang="is" data-title="Mælieining" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Unit%C3%A0_di_misura" title="Unità di misura – Italian" lang="it" hreflang="it" data-title="Unità di misura" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%99%D7%97%D7%99%D7%93%D7%AA_%D7%9E%D7%99%D7%93%D7%94" title="יחידת מידה – Hebrew" lang="he" hreflang="he" data-title="יחידת מידה" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-krc mw-list-item"><a href="https://krc.wikipedia.org/wiki/%D0%81%D0%BB%D1%87%D0%B5%D0%BB%D0%B5%D1%83_%D0%B1%D0%B8%D1%80%D0%B8%D0%BC" title="Ёлчелеу бирим – Karachay-Balkar" lang="krc" hreflang="krc" data-title="Ёлчелеу бирим" data-language-autonym="Къарачай-малкъар" data-language-local-name="Karachay-Balkar" class="interlanguage-link-target"><span>Къарачай-малкъар</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%94%E1%83%A0%E1%83%97%E1%83%94%E1%83%A3%E1%83%9A%E1%83%97%E1%83%90_%E1%83%A1%E1%83%98%E1%83%A1%E1%83%A2%E1%83%94%E1%83%9B%E1%83%94%E1%83%91%E1%83%98" title="ერთეულთა სისტემები – Georgian" lang="ka" hreflang="ka" data-title="ერთეულთა სისტემები" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%91%D1%96%D1%80%D0%BB%D1%96%D0%BA_(%D0%BC%D3%A9%D0%BB%D1%88%D0%B5%D1%80)" title="Бірлік (мөлшер) – Kazakh" lang="kk" hreflang="kk" data-title="Бірлік (мөлшер)" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Kizio" title="Kizio – Swahili" lang="sw" hreflang="sw" data-title="Kizio" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-ht mw-list-item"><a href="https://ht.wikipedia.org/wiki/Inite_mezi" title="Inite mezi – Haitian Creole" lang="ht" hreflang="ht" data-title="Inite mezi" data-language-autonym="Kreyòl ayisyen" data-language-local-name="Haitian Creole" class="interlanguage-link-target"><span>Kreyòl ayisyen</span></a></li><li class="interlanguage-link interwiki-ku mw-list-item"><a href="https://ku.wikipedia.org/wiki/Yekeya_p%C3%AEvan%C3%AA" title="Yekeya pîvanê – Kurdish" lang="ku" hreflang="ku" data-title="Yekeya pîvanê" data-language-autonym="Kurdî" data-language-local-name="Kurdish" class="interlanguage-link-target"><span>Kurdî</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%A4%D0%B8%D0%B7%D0%B8%D0%BA%D0%B0%D0%BB%D1%8B%D0%BA_%D1%87%D0%BE%D2%A3%D0%B4%D1%83%D0%BA%D1%82%D0%B0%D1%80%D0%B4%D1%8B%D0%BD_%D0%B1%D0%B8%D1%80%D0%B4%D0%B8%D0%BA%D1%82%D0%B5%D1%80%D0%B8" title="Физикалык чоңдуктардын бирдиктери – Kyrgyz" lang="ky" hreflang="ky" data-title="Физикалык чоңдуктардын бирдиктери" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/M%C4%93rvien%C4%ABba" title="Mērvienība – Latvian" lang="lv" hreflang="lv" data-title="Mērvienība" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Moosseenheet" title="Moosseenheet – Luxembourgish" lang="lb" hreflang="lb" data-title="Moosseenheet" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Matavimo_vienetas" title="Matavimo vienetas – Lithuanian" lang="lt" hreflang="lt" data-title="Matavimo vienetas" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-lg mw-list-item"><a href="https://lg.wikipedia.org/wiki/Namungina_z%27ebipimo" title="Namungina z'ebipimo – Ganda" lang="lg" hreflang="lg" data-title="Namungina z'ebipimo" data-language-autonym="Luganda" data-language-local-name="Ganda" class="interlanguage-link-target"><span>Luganda</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/M%C3%A9rt%C3%A9kegys%C3%A9g" title="Mértékegység – Hungarian" lang="hu" hreflang="hu" data-title="Mértékegység" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%95%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D0%B0_%D0%BC%D0%B5%D1%80%D0%BA%D0%B0" title="Единица мерка – Macedonian" lang="mk" hreflang="mk" data-title="Единица мерка" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%8F%E0%B4%95%E0%B4%95%E0%B4%82" title="ഏകകം – Malayalam" lang="ml" hreflang="ml" data-title="ഏകകം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%8F%E0%A4%95%E0%A4%95" title="एकक – Marathi" lang="mr" hreflang="mr" data-title="एकक" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Unit_ukuran" title="Unit ukuran – Malay" lang="ms" hreflang="ms" data-title="Unit ukuran" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Natuurkundige_eenheid" title="Natuurkundige eenheid – Dutch" lang="nl" hreflang="nl" data-title="Natuurkundige eenheid" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E7%89%A9%E7%90%86%E5%8D%98%E4%BD%8D" title="物理単位 – Japanese" lang="ja" hreflang="ja" data-title="物理単位" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/M%C3%A5leenhet" title="Måleenhet – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Måleenhet" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/M%C3%A5leining" title="Måleining – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Måleining" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Unitat_de_mesura" title="Unitat de mesura – Occitan" lang="oc" hreflang="oc" data-title="Unitat de mesura" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-om mw-list-item"><a href="https://om.wikipedia.org/wiki/Lakkaantoo_safaraa" title="Lakkaantoo safaraa – Oromo" lang="om" hreflang="om" data-title="Lakkaantoo safaraa" data-language-autonym="Oromoo" data-language-local-name="Oromo" class="interlanguage-link-target"><span>Oromoo</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/O%CA%BBlchov_birligi" title="Oʻlchov birligi – Uzbek" lang="uz" hreflang="uz" data-title="Oʻlchov birligi" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%AE%E0%A8%BE%E0%A8%AA_%E0%A8%87%E0%A8%95%E0%A8%BE%E0%A8%88%E0%A8%86%E0%A8%82" title="ਮਾਪ ਇਕਾਈਆਂ – Punjabi" lang="pa" hreflang="pa" data-title="ਮਾਪ ਇਕਾਈਆਂ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D8%AF_%D8%A7%D9%86%D8%AF%D8%A7%D8%B2%D9%87_%DA%A9%D9%88%D9%84%D9%88_%D9%88%D8%A7%D8%AD%D8%AF" title="د اندازه کولو واحد – Pashto" lang="ps" hreflang="ps" data-title="د اندازه کولو واحد" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target"><span>پښتو</span></a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Maateenheit" title="Maateenheit – Low German" lang="nds" hreflang="nds" data-title="Maateenheit" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target"><span>Plattdüütsch</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Jednostka_miary" title="Jednostka miary – Polish" lang="pl" hreflang="pl" data-title="Jednostka miary" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Unidade_de_medida" title="Unidade de medida – Portuguese" lang="pt" hreflang="pt" data-title="Unidade de medida" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Unitate_de_m%C4%83sur%C4%83" title="Unitate de măsură – Romanian" lang="ro" hreflang="ro" data-title="Unitate de măsură" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/Tupu" title="Tupu – Quechua" lang="qu" hreflang="qu" data-title="Tupu" data-language-autonym="Runa Simi" data-language-local-name="Quechua" class="interlanguage-link-target"><span>Runa Simi</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%95%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D1%8B_%D1%84%D0%B8%D0%B7%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D1%85_%D0%B2%D0%B5%D0%BB%D0%B8%D1%87%D0%B8%D0%BD" title="Единицы физических величин – Russian" lang="ru" hreflang="ru" data-title="Единицы физических величин" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sc mw-list-item"><a href="https://sc.wikipedia.org/wiki/Unidade_de_medida" title="Unidade de medida – Sardinian" lang="sc" hreflang="sc" data-title="Unidade de medida" data-language-autonym="Sardu" data-language-local-name="Sardinian" class="interlanguage-link-target"><span>Sardu</span></a></li><li class="interlanguage-link interwiki-nso mw-list-item"><a href="https://nso.wikipedia.org/wiki/Mot%C5%A1o" title="Motšo – Northern Sotho" lang="nso" hreflang="nso" data-title="Motšo" data-language-autonym="Sesotho sa Leboa" data-language-local-name="Northern Sotho" class="interlanguage-link-target"><span>Sesotho sa Leboa</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Nj%C3%ABsia_mat%C3%ABse" title="Njësia matëse – Albanian" lang="sq" hreflang="sq" data-title="Njësia matëse" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-scn mw-list-item"><a href="https://scn.wikipedia.org/wiki/Unitati_di_misura" title="Unitati di misura – Sicilian" lang="scn" hreflang="scn" data-title="Unitati di misura" data-language-autonym="Sicilianu" data-language-local-name="Sicilian" class="interlanguage-link-target"><span>Sicilianu</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%92%E0%B6%9A%E0%B6%9A_%E0%B7%83%E0%B7%84_%E0%B6%B8%E0%B7%8F%E0%B6%B1" title="ඒකක සහ මාන – Sinhala" lang="si" hreflang="si" data-title="ඒකක සහ මාන" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Unit_of_measurement" title="Unit of measurement – Simple English" lang="en-simple" hreflang="en-simple" data-title="Unit of measurement" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Fyzik%C3%A1lna_jednotka" title="Fyzikálna jednotka – Slovak" lang="sk" hreflang="sk" data-title="Fyzikálna jednotka" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Merska_enota" title="Merska enota – Slovenian" lang="sl" hreflang="sl" data-title="Merska enota" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%DB%8C%DB%95%DA%A9%DB%95%DA%A9%D8%A7%D9%86%DB%8C_%D9%BE%DB%8E%D9%88%D8%A7%D9%86" title="یەکەکانی پێوان – Central Kurdish" lang="ckb" hreflang="ckb" data-title="یەکەکانی پێوان" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%9C%D0%B5%D1%80%D0%BD%D0%B5_%D1%98%D0%B5%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D0%B5" title="Мерне јединице – Serbian" lang="sr" hreflang="sr" data-title="Мерне јединице" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Mjerne_jedinice" title="Mjerne jedinice – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Mjerne jedinice" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Mittayksikk%C3%B6" title="Mittayksikkö – Finnish" lang="fi" hreflang="fi" data-title="Mittayksikkö" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/M%C3%A5ttenhet" title="Måttenhet – Swedish" lang="sv" hreflang="sv" data-title="Måttenhet" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%85%E0%AE%B2%E0%AE%95%E0%AF%81_(%E0%AE%85%E0%AE%B3%E0%AE%B5%E0%AF%88%E0%AE%AF%E0%AE%BF%E0%AE%AF%E0%AE%B2%E0%AF%8D)" title="அலகு (அளவையியல்) – Tamil" lang="ta" hreflang="ta" data-title="அலகு (அளவையியல்)" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-kab mw-list-item"><a href="https://kab.wikipedia.org/wiki/Tigget_n_usekti" title="Tigget n usekti – Kabyle" lang="kab" hreflang="kab" data-title="Tigget n usekti" data-language-autonym="Taqbaylit" data-language-local-name="Kabyle" class="interlanguage-link-target"><span>Taqbaylit</span></a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/%D2%AE%D0%BB%D1%87%D3%99%D2%AF_%D0%B1%D0%B5%D1%80%D3%99%D0%BC%D0%BB%D0%B5%D0%BA%D0%BB%D3%99%D1%80%D0%B5" title="Үлчәү берәмлекләре – Tatar" lang="tt" hreflang="tt" data-title="Үлчәү берәмлекләре" data-language-autonym="Татарча / tatarça" data-language-local-name="Tatar" class="interlanguage-link-target"><span>Татарча / tatarça</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%AA%E0%B1%8D%E0%B0%B0%E0%B0%AE%E0%B0%BE%E0%B0%A3%E0%B0%82" title="ప్రమాణం – Telugu" lang="te" hreflang="te" data-title="ప్రమాణం" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%AB%E0%B8%99%E0%B9%88%E0%B8%A7%E0%B8%A2%E0%B8%A7%E0%B8%B1%E0%B8%94" title="หน่วยวัด – Thai" lang="th" hreflang="th" data-title="หน่วยวัด" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/%D0%92%D0%BE%D2%B3%D0%B8%D0%B4%D2%B3%D0%BE%D0%B8_%D0%B1%D1%83%D0%B7%D1%83%D1%80%D0%B3%D0%B8%D2%B3%D0%BE%D0%B8_%D1%84%D0%B8%D0%B7%D0%B8%D0%BA%D3%A3" title="Воҳидҳои бузургиҳои физикӣ – Tajik" lang="tg" hreflang="tg" data-title="Воҳидҳои бузургиҳои физикӣ" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target"><span>Тоҷикӣ</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/%C3%96l%C3%A7%C3%BC_birimi" title="Ölçü birimi – Turkish" lang="tr" hreflang="tr" data-title="Ölçü birimi" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9E%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D1%8F_%D0%B2%D0%B8%D0%BC%D1%96%D1%80%D1%8E%D0%B2%D0%B0%D0%BD%D0%BD%D1%8F" title="Одиниця вимірювання – Ukrainian" lang="uk" hreflang="uk" data-title="Одиниця вимірювання" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Unit%C3%A0_de_mezura" title="Unità de mezura – Venetian" lang="vec" hreflang="vec" data-title="Unità de mezura" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target"><span>Vèneto</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/%C4%90%C6%A1n_v%E1%BB%8B_%C4%91o" title="Đơn vị đo – Vietnamese" lang="vi" hreflang="vi" data-title="Đơn vị đo" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E8%AE%A1%E9%87%8F%E5%8D%95%E4%BD%8D" title="计量单位 – Wu" lang="wuu" hreflang="wuu" data-title="计量单位" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E8%A8%88%E9%87%8F%E5%96%AE%E4%BD%8D" title="計量單位 – Cantonese" lang="yue" hreflang="yue" data-title="計量單位" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E8%AE%A1%E9%87%8F%E5%8D%95%E4%BD%8D" title="计量单位 – Chinese" lang="zh" hreflang="zh" data-title="计量单位" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-rsk mw-list-item"><a href="https://rsk.wikipedia.org/wiki/%D0%9C%D0%B5%D1%80%D0%BD%D0%B8_%D1%94%D0%B4%D0%B8%D0%BD%D0%BA%D0%B8" title="Мерни єдинки – Pannonian Rusyn" lang="rsk" hreflang="rsk" data-title="Мерни єдинки" data-language-autonym="Руски" data-language-local-name="Pannonian Rusyn" class="interlanguage-link-target"><span>Руски</span></a></li> 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id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"><span class="mw-redirectedfrom">(Redirected from <a href="/w/index.php?title=Unit_of_measure&redirect=no" class="mw-redirect" title="Unit of measure">Unit of measure</a>)</span></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Quantity standard</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Not to be confused with <a href="/wiki/Level_of_measurement" title="Level of measurement">Level of measurement</a>.</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">"Unit of measure" redirects here. For other uses, see <a href="/wiki/Unit_of_measure_(disambiguation)" class="mw-disambig" title="Unit of measure (disambiguation)">Unit of measure (disambiguation)</a>.</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">"Weights and measures" redirects here. For other uses, see <a href="/wiki/Weights_and_measures_(disambiguation)" class="mw-disambig" title="Weights and measures (disambiguation)">Weights and measures (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-More_citations_needed plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Unit_of_measurement" title="Special:EditPage/Unit of measurement">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22Unit+of+measurement%22">"Unit of measurement"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22Unit+of+measurement%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22Unit+of+measurement%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22Unit+of+measurement%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22Unit+of+measurement%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22Unit+of+measurement%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">June 2019</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p class="mw-empty-elt"> </p> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Weights_and_Measures_office.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Weights_and_Measures_office.jpg/330px-Weights_and_Measures_office.jpg" decoding="async" width="330" height="248" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Weights_and_Measures_office.jpg/495px-Weights_and_Measures_office.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Weights_and_Measures_office.jpg/660px-Weights_and_Measures_office.jpg 2x" data-file-width="2048" data-file-height="1536" /></a><figcaption>The former Weights and Measures office in <a href="/wiki/Seven_Sisters,_London" title="Seven Sisters, London">Seven Sisters, London</a></figcaption></figure> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg/330px-Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg" decoding="async" width="330" height="248" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg/495px-Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg/660px-Unit%C3%A0_di_misura_-_Palazzo_della_Ragione_-_Padova.jpg 2x" data-file-width="4320" data-file-height="3240" /></a><figcaption>Units of measurement, <a href="/wiki/Palazzo_della_Ragione,_Padua" title="Palazzo della Ragione, Padua">Palazzo della Ragione, Padua</a></figcaption></figure> <p>A <b>unit of measurement</b>, or <b>unit of measure</b>, is a definite <a href="/wiki/Magnitude_(mathematics)" title="Magnitude (mathematics)">magnitude</a> of a <a href="/wiki/Quantity" title="Quantity">quantity</a>, defined and adopted by convention or by law, that is used as a standard for <a href="/wiki/Measurement" title="Measurement">measurement</a> of the same <a href="/wiki/Kind_of_quantity" class="mw-redirect" title="Kind of quantity">kind of quantity</a>.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Any other quantity of that kind can be expressed as a multiple of the unit of measurement.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>For example, a <a href="/wiki/Length" title="Length">length</a> is a <a href="/wiki/Physical_quantity" title="Physical quantity">physical quantity</a>. The <a href="/wiki/Metre" title="Metre">metre</a> (symbol m) is a unit of length that represents a definite predetermined length. For instance, when referencing "10 metres" (or 10 m), what is actually meant is 10 times the definite predetermined length called "metre". </p><p>The definition, agreement, and practical use of units of measurement have played a crucial role in human endeavour from early ages up to the present. A multitude of <a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">systems of units</a> used to be very common. Now there is a global standard, the <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a> (SI), the modern form of the <a href="/wiki/Metric_system" title="Metric system">metric system</a>. </p><p>In trade, <b>weights and measures</b> are often a subject of governmental regulation, to ensure fairness and transparency. The <a href="/wiki/International_Bureau_of_Weights_and_Measures" title="International Bureau of Weights and Measures">International Bureau of Weights and Measures</a> (BIPM) is tasked with ensuring worldwide uniformity of measurements and their traceability to the International System of Units (SI). </p><p><a href="/wiki/Metrology" title="Metrology">Metrology</a> is the science of developing nationally and internationally accepted units of measurement. </p><p>In <a href="/wiki/Physics" title="Physics">physics</a> and metrology, units are standards for <a href="/wiki/Measurement" title="Measurement">measurement</a> of physical quantities that need clear definitions to be useful. <a href="/wiki/Reproducibility" title="Reproducibility">Reproducibility</a> of experimental results is central to the <a href="/wiki/Scientific_method" title="Scientific method">scientific method</a>. A standard system of units facilitates this. Scientific systems of units are a refinement of the concept of weights and measures historically developed for commercial purposes.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p><a href="/wiki/Science" title="Science">Science</a>, <a href="/wiki/Medicine" title="Medicine">medicine</a>, and <a href="/wiki/Engineering" title="Engineering">engineering</a> often use larger and smaller units of measurement than those used in everyday life. The judicious selection of the units of measurement can aid researchers in <a href="/wiki/Problem_solving" title="Problem solving">problem solving</a> (see, for example, <a href="/wiki/Dimensional_analysis" title="Dimensional analysis">dimensional analysis</a>). </p><p>In the <a href="/wiki/Social_sciences" class="mw-redirect" title="Social sciences">social sciences</a>, there are no standard units of measurement. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/System_of_units_of_measurement#History" title="System of units of measurement">System of units of measurement § History</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/History_of_measurement" title="History of measurement">History of measurement</a></div> <p>A unit of measurement is a standardized <a href="/wiki/Quantity" title="Quantity">quantity</a> of a physical property, used as a factor to express occurring quantities of that property. Units of measurement were among the earliest tools invented by humans. Primitive societies needed rudimentary measures for many tasks: constructing dwellings of an appropriate size and shape, fashioning clothing, or bartering food or raw materials. </p><p>The earliest known uniform systems of measurement seem to have all been created sometime in the <a href="/wiki/4th_millennium_BC" title="4th millennium BC">4th</a> and <a href="/wiki/3rd_millennium_BC" title="3rd millennium BC">3rd millennia BC</a> among the ancient peoples of <a href="/wiki/Mesopotamia" title="Mesopotamia">Mesopotamia</a>, <a href="/wiki/Ancient_Egypt" title="Ancient Egypt">Egypt</a> and the <a href="/wiki/Indus_Valley_civilisation" class="mw-redirect" title="Indus Valley civilisation">Indus Valley</a>, and perhaps also <a href="/wiki/Elam" title="Elam">Elam</a> in <a href="/wiki/Iran" title="Iran">Persia</a> as well. </p><p>Weights and measures are mentioned in the <a href="/wiki/Bible" title="Bible">Bible</a> (Leviticus 19:35–36). It is a commandment to be honest and have fair measures. </p><p>In the <i><a href="/wiki/Magna_Carta" title="Magna Carta">Magna Carta</a></i> of 1215 (The Great Charter) with the seal of <a href="/wiki/John,_King_of_England" title="John, King of England">King John</a>, put before him by the Barons of England, King John agreed in Clause 35 "There shall be one measure of wine throughout our whole realm, and one measure of ale and one measure of corn—namely, the London quart;—and one width of dyed and russet and hauberk cloths—namely, two ells below the selvage..." </p><p>As of the 21st century, the International System is predominantly used in the world. There exist other unit systems which are used in many places such as the United States Customary System and the Imperial System. The United States is the only industrialized country that has not yet at least mostly converted to the metric system.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> The systematic effort to develop a universally acceptable system of units dates back to 1790 when the French National Assembly charged the French Academy of Sciences to come up such a unit system. This system was the precursor to the metric system which was quickly developed in France but did not take on universal acceptance until 1875 when The Metric Convention Treaty was signed by 17 nations. After this treaty was signed, a <a href="/wiki/General_Conference_on_Weights_and_Measures" title="General Conference on Weights and Measures">General Conference of Weights and Measures</a> (CGPM) was established. The CGPM produced the current SI, which was adopted in 1954 at the 10th Conference of Weights and Measures. Currently, the United States is a dual-system society which uses both the SI and the US Customary system.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Using_SI_Units_in_Astronomy_6-0" class="reference"><a href="#cite_note-Using_SI_Units_in_Astronomy-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Systems_of_units">Systems of units</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=2" title="Edit section: Systems of units"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">System of measurement</a></div> <p>The use of a single unit of measurement for some quantity has obvious drawbacks. For example, it is impractical to use the same unit for the distance between two cities and the length of a needle. Thus, historically they would develop independently. One way to make large numbers or small fractions easier to read, is to use <a href="/wiki/Unit_prefixes" class="mw-redirect" title="Unit prefixes">unit prefixes</a>. </p><p>At some point in time though, the need to relate the two units might arise, and consequently the need to choose one unit as defining the other or vice versa. For example, an <a href="/wiki/Inch" title="Inch">inch</a> could be defined in terms of a <a href="/wiki/Barleycorn_(unit)" title="Barleycorn (unit)">barleycorn</a>. A system of measurement is a collection of units of measurement and rules relating them to each other. </p><p>As <a href="/wiki/Science" title="Science">science</a> progressed, a need arose to relate the measurement systems of different quantities, like length and weight and volume. The effort of attempting to relate different traditional systems between each other exposed many inconsistencies, and brought about the development of new units and systems. </p><p>Systems of units vary from country to country. Some of the different systems include the <a href="/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units" title="Centimetre–gram–second system of units">centimetre–gram–second</a>, <a href="/wiki/Foot%E2%80%93pound%E2%80%93second_system_of_units" title="Foot–pound–second system of units">foot–pound–second</a>, <a href="/wiki/MKS_system_of_units" class="mw-redirect" title="MKS system of units">metre–kilogram–second</a> systems, and the <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a>, SI. Among the different systems of units used in the world, the most widely used and internationally accepted one is SI. The <a href="/wiki/SI_base_unit" title="SI base unit">base SI units</a> are the second, metre, kilogram, ampere, kelvin, mole and candela; all <a href="/wiki/SI_derived_unit" title="SI derived unit">other SI units</a> are derived from these base units.<sup id="cite_ref-:0_7-0" class="reference"><a href="#cite_note-:0-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Brochure9_2019_8-0" class="reference"><a href="#cite_note-Brochure9_2019-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 132">: 132 </span></sup> </p><p>Systems of measurement in modern use include the <a href="/wiki/Metric_system" title="Metric system">metric system</a>, the <a href="/wiki/Imperial_system" class="mw-redirect" title="Imperial system">imperial system</a>, and <a href="/wiki/United_States_customary_units" title="United States customary units">United States customary units</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Traditional_systems">Traditional systems</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=3" title="Edit section: Traditional systems"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Historically many of the systems of measurement which had been in use were to some extent based on the dimensions of the human body. Such units, which may be called <a href="/wiki/Anthropic_units" title="Anthropic units">anthropic units</a>, include the <a href="/wiki/Cubit" title="Cubit">cubit</a>, based on the length of the forearm; the <a href="/wiki/Pace_(unit)" title="Pace (unit)">pace</a>, based on the length of a stride; and the <a href="/wiki/Foot_(unit)" title="Foot (unit)">foot</a> and <a href="/wiki/Hand_(unit)" title="Hand (unit)">hand</a>.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 25">: 25 </span></sup> As a result, units of measure could vary not only from location to location but from person to person. Units not based on the human body could be based on agriculture, as is the case with the <a href="/wiki/Furlong" title="Furlong">furlong</a> and the <a href="/wiki/Acre" title="Acre">acre</a>, both based on the amount of land able to be worked by a team of <a href="/wiki/Oxen" class="mw-redirect" title="Oxen">oxen</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Metric_systems">Metric systems</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=4" title="Edit section: Metric systems"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a></div> <p><a href="/wiki/Metric_system" title="Metric system">Metric systems</a> of units have <a href="/wiki/History_of_the_metric_system" title="History of the metric system">evolved since the adoption of the original metric system</a> in <a href="/wiki/France" title="France">France</a> in 1791. The current international standard metric system is the <a href="/wiki/SI" class="mw-redirect" title="SI">International System of Units</a> (abbreviated to SI). An important feature of modern systems is <a href="/wiki/Standardization" title="Standardization">standardization</a>. Each unit has a universally recognized size. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Tabella_conversione_metrica_1860_MG_7771.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Tabella_conversione_metrica_1860_MG_7771.jpg/220px-Tabella_conversione_metrica_1860_MG_7771.jpg" decoding="async" width="220" height="225" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Tabella_conversione_metrica_1860_MG_7771.jpg/330px-Tabella_conversione_metrica_1860_MG_7771.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Tabella_conversione_metrica_1860_MG_7771.jpg/440px-Tabella_conversione_metrica_1860_MG_7771.jpg 2x" data-file-width="2438" data-file-height="2494" /></a><figcaption>An example of <a href="/wiki/Metrication" title="Metrication">metrication</a> in 1860 when Tuscany became part of modern Italy (ex. one "libbra" = 339.54 grams)</figcaption></figure> <p>Both the <a href="/wiki/Imperial_units" title="Imperial units">imperial units</a> and <a href="/wiki/US_customary_units" class="mw-redirect" title="US customary units">US customary units</a> derive from earlier <a href="/wiki/English_unit" class="mw-redirect" title="English unit">English units</a>. Imperial units were mostly used in the <a href="/wiki/Commonwealth_of_Nations" title="Commonwealth of Nations">British Commonwealth</a> and the former <a href="/wiki/British_Empire" title="British Empire">British Empire</a>. US customary units are still the main system of measurement used in the <a href="/wiki/United_States" title="United States">United States</a> outside of science, medicine, many sectors of industry, and some of government and military, and despite Congress having legally authorised metric measure on 28 July 1866.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> Some steps towards US <a href="/wiki/Metrication" title="Metrication">metrication</a> have been made, particularly the redefinition of basic US and imperial units to derive exactly from SI units. Since the <a href="/wiki/International_yard_and_pound" title="International yard and pound">international yard and pound</a> agreement of 1959 the US and imperial inch is now defined as exactly <span class="nowrap"><span data-sort-value="6998254000000000000♠"></span>0.0254 <a href="/wiki/Metre" title="Metre">m</a></span>, and the US and imperial avoirdupois pound is now defined as exactly <span class="nowrap"><span data-sort-value="6999453592370000000♠"></span>0.453<span style="margin-left:.25em;">592</span><span style="margin-left:.25em;">37</span> <a href="/wiki/Kilogram" title="Kilogram">kg</a></span>.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Natural_systems">Natural systems</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=5" title="Edit section: Natural systems"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Natural_units" title="Natural units">Natural units</a></div> <p>While the above systems of units are based on arbitrary unit values, formalised as standards, <a href="/wiki/Natural_units" title="Natural units">natural units</a> in physics are based on physical principle or are selected to make physical equations easier to work with. For example, <a href="/wiki/Atomic_units" title="Atomic units">atomic units</a> (au) were designed to simplify the wave equation in <a href="/wiki/Atomic_physics" title="Atomic physics">atomic physics</a>.<sup id="cite_ref-Hartree28_12-0" class="reference"><a href="#cite_note-Hartree28-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>Some <a href="/wiki/List_of_unusual_units_of_measurement" title="List of unusual units of measurement">unusual and non-standard units</a> may be encountered in sciences. These may include the <a href="/wiki/Solar_mass" title="Solar mass">solar mass</a> (<span class="nowrap"><span data-sort-value="7030200000000000000♠"></span>2<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>30</sup> kg</span>), the <a href="/wiki/TNT_equivalent" title="TNT equivalent">megaton</a> (the energy released by detonating one million tons of <a href="/wiki/Trinitrotoluene" class="mw-redirect" title="Trinitrotoluene">trinitrotoluene</a>, TNT) and the <a href="/wiki/Electronvolt" title="Electronvolt">electronvolt</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Legal_control_of_weights_and_measures">Legal control of weights and measures</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=6" title="Edit section: Legal control of weights and measures"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>To reduce the incidence of retail fraud, many national <a href="/wiki/Statutes" class="mw-redirect" title="Statutes">statutes</a> have standard definitions of weights and measures that may be used (hence "<a href="/wiki/Statute_measure" class="mw-redirect" title="Statute measure">statute measure</a>"), and these are verified by legal officers.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2019)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="Informal_comparison_to_familiar_concepts">Informal comparison to familiar concepts</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=7" title="Edit section: Informal comparison to familiar concepts"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/List_of_unusual_units_of_measurement" title="List of unusual units of measurement">List of unusual units of measurement</a></div> <p>In informal settings, a quantity may be described as multiples of that of a familiar entity, which can be easier to contextualize than a value in a formal unit system. For instance, a publication may describe an area in a foreign country as a number of multiples of the area of a region local to the readership. The propensity for certain concepts to be used frequently can give rise to loosely defined "systems" of units.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Base_and_derived_units">Base and derived units</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=8" title="Edit section: Base and derived units"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Base_unit_of_measurement" title="Base unit of measurement">Base unit of measurement</a></div> <p>For most quantities a unit is necessary to communicate values of that physical quantity. For example, conveying to someone a particular length without using some sort of unit is impossible, because a length cannot be described without a reference used to make sense of the value given. </p><p>But not all quantities require a unit of their own. Using physical laws, units of quantities can be expressed as combinations of units of other quantities. Thus only a small set of units is required. These units are taken as the <i>base units</i> and the other units are <i>derived units</i>. Thus base units are the units of the quantities which are independent of other quantities and they are the units of length, mass, time, electric current, temperature, luminous intensity and the amount of substance. Derived units are the units of the quantities which are derived from the base quantities and some of the derived units are the units of speed, work, acceleration, energy, pressure etc.<sup id="cite_ref-:0_7-1" class="reference"><a href="#cite_note-:0-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p>Different systems of units are based on different choices of a set of related units including fundamental and derived units. </p> <div class="mw-heading mw-heading2"><h2 id="Physical_quantity_components">Physical quantity components</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=9" title="Edit section: Physical quantity components"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="excerpt-block"><style data-mw-deduplicate="TemplateStyles:r1066933788">.mw-parser-output .excerpt-hat .mw-editsection-like{font-style:normal}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable dablink excerpt-hat selfref">This section is an excerpt from <a href="/wiki/Physical_quantity#Components" title="Physical quantity">Physical quantity § Components</a>.<span class="mw-editsection-like plainlinks"><span class="mw-editsection-bracket">[</span><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Physical_quantity&action=edit#Components">edit</a><span class="mw-editsection-bracket">]</span></span></div><div class="excerpt"> <p>Following <a href="/wiki/ISO_80000-1" class="mw-redirect" title="ISO 80000-1">ISO 80000-1</a>,<sup id="cite_ref-Physical_quantity_ISO_80000-1_15-0" class="reference"><a href="#cite_note-Physical_quantity_ISO_80000-1-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> any value or <a href="/wiki/Magnitude_(mathematics)" title="Magnitude (mathematics)">magnitude</a> of a physical quantity is expressed as a comparison to a unit of that quantity. The <i>value</i> of a physical quantity <i>Z</i> is expressed as the product of a <i>numerical value</i> {<i>Z</i>} (a pure number) and a unit [<i>Z</i>]: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Z=\{Z\}\times [Z]}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Z</mi> <mo>=</mo> <mo fence="false" stretchy="false">{</mo> <mi>Z</mi> <mo fence="false" stretchy="false">}</mo> <mo>×</mo> <mo stretchy="false">[</mo> <mi>Z</mi> <mo stretchy="false">]</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Z=\{Z\}\times [Z]}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/def9bab2222172f53c7a8becf5e4185293817ff6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.599ex; height:2.843ex;" alt="{\displaystyle Z=\{Z\}\times [Z]}"></span></dd></dl> <p>For example, let <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Z}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Z</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Z}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1cc6b75e09a8aa3f04d8584b11db534f88fb56bd" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.68ex; height:2.176ex;" alt="{\displaystyle Z}"></span> be "2 metres"; then, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \{Z\}=2}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">{</mo> <mi>Z</mi> <mo fence="false" stretchy="false">}</mo> <mo>=</mo> <mn>2</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \{Z\}=2}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c9f3e204327b8ad2f7bc390aac76ce1c24ca13fe" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:8.266ex; height:2.843ex;" alt="{\displaystyle \{Z\}=2}"></span> is the numerical value and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle [Z]=\mathrm {metre} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">[</mo> <mi>Z</mi> <mo stretchy="false">]</mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">t</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">e</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle [Z]=\mathrm {metre} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f6a8ec250d9a5d8cc852b7f4f0942e1753dbffd7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:11.889ex; height:2.843ex;" alt="{\displaystyle [Z]=\mathrm {metre} }"></span> is the unit. Conversely, the numerical value expressed in an arbitrary unit can be obtained as: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \{Z\}=Z/[Z]}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">{</mo> <mi>Z</mi> <mo fence="false" stretchy="false">}</mo> <mo>=</mo> <mi>Z</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mo stretchy="false">[</mo> <mi>Z</mi> <mo stretchy="false">]</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \{Z\}=Z/[Z]}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3f34ded144b10ed1870ed60970d3e48a6a968381" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:12.921ex; height:2.843ex;" alt="{\displaystyle \{Z\}=Z/[Z]}"></span></dd></dl> The multiplication sign is usually left out, just as it is left out between variables in the scientific notation of formulas. The convention used to express quantities is referred to as <i><a href="/wiki/Quantity_calculus" title="Quantity calculus">quantity calculus</a></i>. In formulas, the unit [<i>Z</i>] can be treated as if it were a specific magnitude of a kind of physical <a href="/wiki/Dimension" title="Dimension">dimension</a>: see <i><a href="/wiki/Dimensional_analysis" title="Dimensional analysis">Dimensional analysis</a></i> for more on this treatment.</div></div> <div class="mw-heading mw-heading2"><h2 id="Dimensional_homogeneity">Dimensional homogeneity</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=10" title="Edit section: Dimensional homogeneity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Dimensional_homogeneity" class="mw-redirect" title="Dimensional homogeneity">Dimensional homogeneity</a></div> <p>Units can only be added or subtracted if they are the same type; however units can always be multiplied or divided, as <a href="/wiki/George_Gamow" title="George Gamow">George Gamow</a> used to explain. Let <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Z}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Z</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Z}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1cc6b75e09a8aa3f04d8584b11db534f88fb56bd" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.68ex; height:2.176ex;" alt="{\displaystyle Z}"></span> be "2 metres" and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle W}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>W</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle W}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/54a9c4c547f4d6111f81946cad242b18298d70b7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.435ex; height:2.176ex;" alt="{\displaystyle W}"></span> "3 seconds", then </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 2\,\mathrm {metres} \times 3\,\mathrm {seconds} =\{Z\}\{W\}\times [Z][W]=6\,\mathrm {metres} \times \mathrm {seconds} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>2</mn> <mspace width="thinmathspace" /> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">t</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">s</mi> </mrow> <mo>×</mo> <mn>3</mn> <mspace width="thinmathspace" /> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">s</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">c</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">n</mi> <mi mathvariant="normal">d</mi> <mi mathvariant="normal">s</mi> </mrow> <mo>=</mo> <mo fence="false" stretchy="false">{</mo> <mi>Z</mi> <mo fence="false" stretchy="false">}</mo> <mo fence="false" stretchy="false">{</mo> <mi>W</mi> <mo fence="false" stretchy="false">}</mo> <mo>×</mo> <mo stretchy="false">[</mo> <mi>Z</mi> <mo stretchy="false">]</mo> <mo stretchy="false">[</mo> <mi>W</mi> <mo stretchy="false">]</mo> <mo>=</mo> <mn>6</mn> <mspace width="thinmathspace" /> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">t</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">s</mi> </mrow> <mo>×</mo> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">s</mi> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">c</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">n</mi> <mi mathvariant="normal">d</mi> <mi mathvariant="normal">s</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 2\,\mathrm {metres} \times 3\,\mathrm {seconds} =\{Z\}\{W\}\times [Z][W]=6\,\mathrm {metres} \times \mathrm {seconds} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/eaad7f2e07c031f027c9064fad5a78e0b6fd7fe5" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:63.591ex; height:2.843ex;" alt="{\displaystyle 2\,\mathrm {metres} \times 3\,\mathrm {seconds} =\{Z\}\{W\}\times [Z][W]=6\,\mathrm {metres} \times \mathrm {seconds} }"></span>.</dd></dl> <p>There are certain rules that apply to units: </p> <ul><li>Only like terms may be added. When a unit is divided by itself, the division yields a unitless one. When two different units are multiplied or divided, the result is a new unit, referred to by the combination of the units. For instance, in SI, the unit of speed is metre per second (m/s). See <a href="/wiki/Dimensional_analysis" title="Dimensional analysis">dimensional analysis</a>. A unit can be multiplied by itself, creating a unit with an exponent (e.g. m<sup>2</sup>/s<sup>2</sup>). Put simply, units obey the laws of indices. (See <a href="/wiki/Exponentiation" title="Exponentiation">Exponentiation</a>.)</li> <li>Some units have special names, however these should be treated like their equivalents. For example, one newton (N) is equivalent to 1 kg⋅m/s<sup>2</sup>. Thus a quantity may have several unit designations, for example: the unit for <a href="/wiki/Surface_tension" title="Surface tension">surface tension</a> can be referred to as either N/m (newton per metre) or kg/s<sup>2</sup> (kilogram per second squared).</li></ul> <div class="mw-heading mw-heading2"><h2 id="Converting_units_of_measurement">Converting units of measurement</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=11" title="Edit section: Converting units of measurement"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="excerpt-block"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1066933788"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable dablink excerpt-hat selfref">This section is an excerpt from <a href="/wiki/Conversion_of_units" title="Conversion of units">Conversion of units</a>.<span class="mw-editsection-like plainlinks"><span class="mw-editsection-bracket">[</span><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Conversion_of_units&action=edit">edit</a><span class="mw-editsection-bracket">]</span></span></div><div class="excerpt"> <p><a href="/wiki/Conversion_of_units" title="Conversion of units">Conversion of units</a> is the conversion of the unit of measurement in which a <a href="/wiki/Quantity" title="Quantity">quantity</a> is expressed, typically through a multiplicative conversion factor that changes the unit without changing the quantity. This is also often loosely taken to include replacement of a quantity with a corresponding quantity that describes the same physical property. </p> Unit conversion is often easier within a <a href="/wiki/Metric_system" title="Metric system">metric system</a> such as the <a href="/wiki/International_System_of_Units" title="International System of Units">SI</a> than in others, due to the system's <a href="/wiki/Coherence_(units_of_measurement)" title="Coherence (units of measurement)">coherence</a> and its <a href="/wiki/Metric_prefix" title="Metric prefix">metric prefixes</a> that act as power-of-10 multipliers.</div></div> <div class="mw-heading mw-heading2"><h2 id="Real-world_implications">Real-world implications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=12" title="Edit section: Real-world implications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One example of the importance of agreed units is the failure of the <a href="/wiki/NASA" title="NASA">NASA</a> <a href="/wiki/Mars_Climate_Orbiter" title="Mars Climate Orbiter">Mars Climate Orbiter</a>, which was accidentally destroyed on a mission to Mars in September 1999 (instead of entering orbit) due to miscommunications about the value of forces: different computer programs used different units of measurement (<a href="/wiki/Newton_(unit)" title="Newton (unit)">newton</a> versus <a href="/wiki/Pound_force" class="mw-redirect" title="Pound force">pound force</a>). Considerable amounts of effort, time, and money were wasted.<sup id="cite_ref-mixups_16-0" class="reference"><a href="#cite_note-mixups-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p><p>On 15 April 1999, <a href="/wiki/Korean_Air" title="Korean Air">Korean Air</a> cargo <a href="/wiki/Korean_Air_Cargo_Flight_6316" title="Korean Air Cargo Flight 6316">flight 6316</a> from <a href="/wiki/Shanghai" title="Shanghai">Shanghai</a> to <a href="/wiki/Seoul" title="Seoul">Seoul</a> was lost due to the crew confusing tower instructions (in metres) and altimeter readings (in feet). Three crew and five people on the ground were killed. Thirty-seven were injured.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p><p>In 1983, a Boeing 767 (which thanks to its pilot's gliding skills landed safely and became known as the <a href="/wiki/Gimli_Glider" title="Gimli Glider">Gimli Glider</a>) ran out of fuel in mid-flight because of two mistakes in figuring the fuel supply of <a href="/wiki/Air_Canada" title="Air Canada">Air Canada</a>'s first aircraft to use metric measurements.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> This accident was the result of both confusion due to the simultaneous use of metric and Imperial measures and confusion of mass and volume measures. </p><p>When planning his journey across the Atlantic Ocean in the 1480s, <a href="/wiki/Christopher_Columbus" title="Christopher Columbus">Columbus</a> mistakenly assumed that the <a href="/wiki/Mile" title="Mile">mile</a> referred to in the Arabic estimate of <style data-mw-deduplicate="TemplateStyles:r1214402035">.mw-parser-output .sfrac{white-space:nowrap}.mw-parser-output .sfrac.tion,.mw-parser-output .sfrac .tion{display:inline-block;vertical-align:-0.5em;font-size:85%;text-align:center}.mw-parser-output .sfrac .num{display:block;line-height:1em;margin:0.0em 0.1em;border-bottom:1px solid}.mw-parser-output .sfrac .den{display:block;line-height:1em;margin:0.1em 0.1em}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style><span class="sfrac">⁠56<span class="sr-only">+</span><span class="tion"><span class="num">2</span><span class="sr-only">/</span><span class="den">3</span></span>⁠</span> miles for the size of a <a href="/wiki/Degree_(angle)" title="Degree (angle)">degree</a> was the same as the actually much shorter Italian mile of 1,480 metres. His estimate for the size of the degree and for the circumference of the Earth was therefore about 25% too small.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 1">: 1 </span></sup><sup class="reference nowrap"><span title="Page / location: 17">: 17 </span></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=13" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Outline_of_metrology_and_measurement" title="Outline of metrology and measurement">Outline of metrology and measurement</a></div> <ul><li><a href="/wiki/Dimensional_metrology" title="Dimensional metrology">Dimensional metrology</a></li> <li><a href="/wiki/Forensic_metrology" title="Forensic metrology">Forensic metrology</a></li> <li><a href="/wiki/Smart_Metrology" title="Smart Metrology">Smart Metrology</a></li> <li><a href="/wiki/Time_metrology" class="mw-redirect" title="Time metrology">Time metrology</a></li> <li><a href="/wiki/Quantum_metrology" title="Quantum metrology">Quantum metrology</a></li> <li><a href="/wiki/GNU_Units" title="GNU Units">GNU Units</a></li> <li><a href="/wiki/List_of_humorous_units_of_measurement" title="List of humorous units of measurement">List of humorous units of measurement</a></li> <li><a href="/wiki/List_of_obsolete_units_of_measurement" title="List of obsolete units of measurement">List of obsolete units of measurement</a></li> <li><a href="/wiki/List_of_unusual_units_of_measurement" title="List of unusual units of measurement">List of unusual units of measurement</a></li> <li><a href="/wiki/Measure_word" title="Measure word">Measure word</a></li> <li><a href="/wiki/List_of_metric_units" title="List of metric units">List of metric units</a></li> <li><a href="/wiki/Numerical-value_equation" class="mw-redirect" title="Numerical-value equation">Numerical-value equation</a></li> <li><a href="/wiki/Scottish_units" title="Scottish units">Scottish units</a></li> <li><a href="/wiki/Seconds_pendulum" title="Seconds pendulum">Seconds pendulum</a></li> <li><a href="/wiki/Space_(punctuation)#Unit_symbols_and_numbers" title="Space (punctuation)">Space (punctuation)#Unit symbols and numbers</a></li> <li><a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">System of measurement</a></li> <li><a href="/wiki/Unified_Code_for_Units_of_Measure" title="Unified Code for Units of Measure">Unified Code for Units of Measure</a></li> <li><a href="/wiki/United_States_customary_units" title="United States customary units">United States customary units</a></li> <li><a href="/wiki/Unit_of_account" title="Unit of account">Unit of account</a></li> <li><a href="/wiki/Units_of_information" title="Units of information">Units of information</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=14" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation encyclopaedia cs1 cs1-prop-foreign-lang-source">"measurement unit". <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110607012159/http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf"><i>International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM)</i></a> <span class="cs1-format">(PDF)</span> (in English and French) (3rd ed.). Joint Committee for Guides in Metrology. 2008. pp. 6–7. 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New York: American Geographical Society, 1924.<a rel="nofollow" class="external text" href="https://archive.org/stream/geographicalconc00nunn#page/n14/mode/1up">1–2</a><a rel="nofollow" class="external text" href="https://archive.org/stream/geographicalconc00nunn#page/n14/mode/1up">17-18</a></span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_measurement&action=edit&section=15" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/45px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/59px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Units_of_measure" class="extiw" title="commons:Category:Units of measure">Units of measure</a></span>.</div></div> </div> <ul><li>Rowlett, Russ (2018) <a rel="nofollow" class="external text" href="https://www.ibiblio.org/units/">How Many? A Dictionary of Units of Measurement</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20111017035501/http://ts.nist.gov/WeightsAndMeasures/Publications/H44-09.cfm">NIST Handbook 44</a>, <i>Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices</i></li> <li><a rel="nofollow" class="external text" href="http://www.bipm.org/en/measurement-units/">Official SI website</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160729171456/http://quantitysystem.codeplex.com/">Quantity System Framework</a> – Quantity System Library and Calculator for Units Conversions and Quantities predictions</li> <li><a rel="nofollow" class="external text" href="http://www.tritechresearch.com/conversions.html">List of units with selected conversion factors</a></li></ul> <p><b>Historical</b> </p> <ul><li><a rel="nofollow" class="external text" href="http://www.wdl.org/en/item/2847">"Arithmetic Conventions for Conversion Between Roman [i.e. Ottoman] and Egyptian Measurement"</a> is a manuscript from 1642, in Arabic, which is about units of measurement.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation encyclopaedia cs1"><span class="cs1-ws-icon" title="s:The New International Encyclopædia/Weights and Measures"><a class="external text" href="https://en.wikisource.org/wiki/The_New_International_Encyclop%C3%A6dia/Weights_and_Measures">"Weights and Measures" </a></span>. <i><a href="/wiki/New_International_Encyclopedia" class="mw-redirect" title="New International Encyclopedia">New International Encyclopedia</a></i>. 1905.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Weights+and+Measures&rft.btitle=New+International+Encyclopedia&rft.date=1905&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+measurement" class="Z3988"></span></li></ul> <p><b>Legal</b> </p> <ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20150402104216/http://www.irishstatutebook.ie/1996/en/act/pub/0027/">Ireland – Metrology Act 1996</a></li> <li><a rel="nofollow" class="external text" href="https://www.legislation.gov.uk/uksi/1995/1804">Text of the Units of Measurement Regulations 1995</a> as in force today (including any amendments) within the United Kingdom, from <a href="/wiki/Legislation.gov.uk" title="Legislation.gov.uk">legislation.gov.uk</a>.</li></ul> <p><b>Metric information</b> </p> <ul><li><a rel="nofollow" class="external text" href="http://www.bipm.org/en/measurement-units/">BIPM</a> (official site)</li> <li><a rel="nofollow" class="external text" href="https://ucum.org/trac">The Unified Code for Units of Measure</a> (UCUM)</li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist 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.navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Systems_of_measurement" title="Template:Systems of measurement"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Systems_of_measurement" title="Template talk:Systems of measurement"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Systems_of_measurement" title="Special:EditPage/Template:Systems of measurement"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Systems_of_measurement" style="font-size:114%;margin:0 4em"><a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">Systems of measurement</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Current</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em">General</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units (SI)</a></li> <li><a href="/wiki/Imperial_units" title="Imperial units">UK imperial system</a></li> <li><a href="/wiki/United_States_customary_units" title="United States customary units">US customary units (USCS/USC)</a></li> <li><a href="/wiki/Chinese_units_of_measurement" title="Chinese units of measurement">Chinese</a> <ul><li><a href="/wiki/Hong_Kong_units_of_measurement" title="Hong Kong units of measurement">Hong Kong</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Specific</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apothecaries%27_system" title="Apothecaries' system">Apothecaries'</a></li> <li><a href="/wiki/Avoirdupois_system" class="mw-redirect" title="Avoirdupois system">Avoirdupois</a></li> <li><a href="/wiki/Troy_weight" title="Troy weight">Troy</a></li> <li><a href="/wiki/Astronomical_system_of_units" title="Astronomical system of units">Astronomical</a></li> <li><a href="/wiki/Conventional_electrical_unit" title="Conventional electrical unit">Electrical</a></li> <li><a href="/wiki/English_Engineering_Units" title="English Engineering Units">English Engineering Units</a> (US)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Natural_units" title="Natural units">Natural</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Atomic_units" title="Atomic units">Atomic</a></li> <li><a href="/wiki/Geometrized_unit_system" title="Geometrized unit system">Geometrised</a></li> <li><a href="/wiki/Heaviside%E2%80%93Lorentz_units" title="Heaviside–Lorentz units">Heaviside–Lorentz</a></li> <li><a href="/wiki/Planck_units" title="Planck units">Planck</a></li> <li><a href="/wiki/Natural_units#Quantum_chromodynamics_units" title="Natural units">Quantum chromodynamical</a></li> <li><a href="/wiki/Stoney_units" title="Stoney units">Stoney</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Background</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em">Metric</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Metric_system" title="Metric system">Overview</a></li> <li><a href="/wiki/Outline_of_the_metric_system" title="Outline of the metric system">Outline</a></li> <li><a href="/wiki/History_of_the_metric_system" title="History of the metric system">History</a></li> <li><a href="/wiki/Metrication" title="Metrication">Metrication</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">UK/US</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Imperial_and_US_customary_measurement_systems" title="Imperial and US customary measurement systems">Overview</a></li> <li><a href="/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems" title="Comparison of the imperial and US customary measurement systems">Comparison</a></li> <li><a href="/wiki/Foot%E2%80%93pound%E2%80%93second_system" class="mw-redirect" title="Foot–pound–second system">Foot–pound–second</a> (FPS)</li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Historic</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em">Metric</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/MKS_system_of_units" class="mw-redirect" title="MKS system of units">metre–kilogram–second</a> (MKS)</li> <li><a href="/wiki/Metre%E2%80%93tonne%E2%80%93second_system_of_units" title="Metre–tonne–second system of units">metre–tonne–second</a> (MTS)</li> <li><a href="/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units" title="Centimetre–gram–second system of units">centimetre–gram–second</a> (CGS)</li> <li><a href="/wiki/Gravitational_metric_system" title="Gravitational metric system">gravitational</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Europe</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Old_Cornish_units_of_measurement" title="Old Cornish units of measurement">Cornish</a></li> <li><a href="/wiki/Cypriot_units_of_measurement" title="Cypriot units of measurement">Cypriot</a></li> <li><a href="/wiki/Czech_units_of_measurement" title="Czech units of measurement">Czech</a></li> <li><a href="/wiki/Danish_units_of_measurement" title="Danish units of measurement">Danish</a></li> <li><a href="/wiki/Dutch_units_of_measurement" title="Dutch units of measurement">Dutch</a></li> <li><a href="/wiki/English_units" title="English units">English</a> <ul><li><a href="/wiki/Winchester_measure" title="Winchester measure">Winchester</a></li> <li><a href="/wiki/Exchequer_Standards" title="Exchequer Standards">Exchequer</a></li></ul></li> <li><a href="/wiki/Estonian_units_of_measurement" title="Estonian units of measurement">Estonian</a></li> <li><a href="/wiki/Obsolete_Finnish_units_of_measurement" title="Obsolete Finnish units of measurement">Finnish</a></li> <li><a href="/wiki/French_units_of_measurement" title="French units of measurement">French</a> <ul><li><a href="/wiki/Traditional_French_units_of_measurement" title="Traditional French units of measurement">Traditional</a></li> <li><a href="/wiki/Mesures_usuelles" title="Mesures usuelles">Mesures usuelles</a></li></ul></li> <li><a href="/wiki/Obsolete_German_units_of_measurement" class="mw-redirect" title="Obsolete German units of measurement">German</a></li> <li><a href="/wiki/Greek_units_of_measurement" title="Greek units of measurement">Greek</a> <ul><li><a href="/wiki/Byzantine_units_of_measurement" title="Byzantine units of measurement">Byzantine</a></li></ul></li> <li><a href="/wiki/Hungarian_units_of_measurement" title="Hungarian units of measurement">Hungarian</a></li> <li><a href="/wiki/Icelandic_units_of_measurement" title="Icelandic units of measurement">Icelandic</a></li> <li><a href="/wiki/Old_Irish_units_of_measurement" class="mw-redirect" title="Old Irish units of measurement">Irish</a></li> <li><a href="/wiki/Italian_units_of_measurement" title="Italian units of measurement">Italian</a></li> <li><a href="/wiki/Latvian_units_of_measurement" title="Latvian units of measurement">Latvian</a></li> <li><a href="/wiki/Luxembourgian_units_of_measurement" class="mw-redirect" title="Luxembourgian units of measurement">Luxembourgian</a></li> <li><a href="/wiki/Maltese_units_of_measurement" title="Maltese units of measurement">Maltese</a></li> <li><a href="/wiki/Norwegian_units_of_measurement" title="Norwegian units of measurement">Norwegian</a></li> <li><a href="/wiki/Ottoman_units_of_measurement" title="Ottoman units of measurement">Ottoman</a></li> <li><a href="/wiki/Polish_units_of_measurement" title="Polish units of measurement">Polish</a></li> <li><a href="/wiki/Portuguese_units_of_measurement" title="Portuguese units of measurement">Portuguese</a></li> <li><a href="/wiki/Romanian_units_of_measurement" title="Romanian units of measurement">Romanian</a></li> <li><a href="/wiki/Obsolete_Russian_units_of_measurement" class="mw-redirect" title="Obsolete Russian units of measurement">Russian</a></li> <li><a href="/wiki/Scottish_units" title="Scottish units">Scottish</a></li> <li><a href="/wiki/Obsolete_Serbian_units_of_measurement" title="Obsolete Serbian units of measurement">Serbian</a></li> <li><a href="/wiki/Slovak_units_of_measurement" title="Slovak units of measurement">Slovak</a></li> <li><a href="/wiki/Spanish_units_of_measurement" title="Spanish units of measurement">Spanish</a></li> <li><a href="/wiki/Swedish_units_of_measurement" title="Swedish units of measurement">Swedish</a></li> <li><a href="/wiki/Swiss_units_of_measurement" title="Swiss units of measurement">Swiss</a></li> <li><a href="/wiki/Welsh_units" title="Welsh units">Welsh</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Asia</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Afghan_units_of_measurement" title="Afghan units of measurement">Afghan</a></li> <li><a href="/wiki/Cambodian_units_of_measurement" title="Cambodian units of measurement">Cambodian</a></li> <li><a href="/wiki/Indian_units_of_measurement" title="Indian units of measurement">Indian</a></li> <li><a href="/wiki/Indonesian_units_of_measurement" title="Indonesian units of measurement">Indonesian</a></li> <li><a href="/wiki/Japanese_units_of_measurement" title="Japanese units of measurement">Japanese</a></li> <li><a href="/wiki/Korean_units_of_measurement" title="Korean units of measurement">Korean</a></li> <li><a href="/wiki/Mongolian_units" title="Mongolian units">Mongolian</a></li> <li><a href="/wiki/Myanmar_units_of_measurement" title="Myanmar units of measurement">Myanmar</a></li> <li><a href="/wiki/Nepalese_customary_units_of_measurement" title="Nepalese customary units of measurement">Nepalese</a></li> <li><a href="/wiki/Omani_units_of_measurement" title="Omani units of measurement">Omani</a></li> <li><a href="/wiki/History_of_measurement_systems_in_Pakistan" title="History of measurement systems in Pakistan">Pakistani</a></li> <li><a href="/wiki/Philippine_units_of_measurement" title="Philippine units of measurement">Philippine</a></li> <li><a href="/wiki/Abucco" title="Abucco">Pegu</a></li> <li><a href="/wiki/Singaporean_units_of_measurement" title="Singaporean units of measurement">Singaporean</a></li> <li><a href="/wiki/Sri_Lankan_units_of_measurement" title="Sri Lankan units of measurement">Sri Lankan</a></li> <li><a href="/wiki/Syrian_units_of_measurement" title="Syrian units of measurement">Syrian</a></li> <li><a href="/wiki/Taiwanese_units_of_measurement" title="Taiwanese units of measurement">Taiwanese</a></li> <li><a href="/wiki/Obsolete_Tatar_units_of_measurement" class="mw-redirect" title="Obsolete Tatar units of measurement">Tatar</a></li> <li><a href="/wiki/Thai_units_of_measurement" title="Thai units of measurement">Thai</a></li> <li><a href="/wiki/Vietnamese_units_of_measurement" title="Vietnamese units of measurement">Vietnamese</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Africa</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Algerian_units_of_measurement" title="Algerian units of measurement">Algerian</a></li> <li><a href="/wiki/Ethiopian_units_of_measurement" title="Ethiopian units of measurement">Ethiopian</a></li> <li><a href="/wiki/Egyptian_units_of_measurement" title="Egyptian units of measurement">Egyptian</a></li> <li><a href="/wiki/Eritrean_units_of_measurement" title="Eritrean units of measurement">Eritrean</a></li> <li><a href="/wiki/Guinean_units_of_measurement" title="Guinean units of measurement">Guinean</a></li> <li><a href="/wiki/Libyan_units_of_measurement" title="Libyan units of measurement">Libyan</a></li> <li><a href="/wiki/Malagasy_units_of_measurement" title="Malagasy units of measurement">Malagasy</a></li> <li><a href="/wiki/Mauritian_units_of_measurement" title="Mauritian units of measurement">Mauritian</a></li> <li><a href="/wiki/Moroccan_units_of_measurement" title="Moroccan units of measurement">Moroccan</a></li> <li><a href="/wiki/Seychellois_units_of_measurement" title="Seychellois units of measurement">Seychellois</a></li> <li><a href="/wiki/Somali_units_of_measurement" title="Somali units of measurement">Somali</a></li> <li><a href="/wiki/South_African_units_of_measurement" title="South African units of measurement">South African</a></li> <li><a href="/wiki/Tunisian_units_of_measurement" title="Tunisian units of measurement">Tunisian</a></li> <li><a href="/wiki/Tanzanian_units_of_measurement" title="Tanzanian units of measurement">Tanzanian</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">North America</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Costa_Rican_units_of_measurement" title="Costa Rican units of measurement">Costa Rican</a></li> <li><a href="/wiki/Cuban_units_of_measurement" title="Cuban units of measurement">Cuban</a></li> <li><a href="/wiki/Haitian_units_of_measurement" title="Haitian units of measurement">Haitian</a></li> <li><a href="/wiki/Honduran_units_of_measurement" title="Honduran units of measurement">Honduran</a></li> <li><a href="/wiki/Mexican_units_of_measurement" title="Mexican units of measurement">Mexican</a></li> <li><a href="/wiki/Nicaraguan_units_of_measurement" title="Nicaraguan units of measurement">Nicaraguan</a></li> <li><a href="/wiki/Puerto_Rican_units_of_measurement" title="Puerto Rican units of measurement">Puerto Rican</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">South America</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Argentine_units_of_measurement" title="Argentine units of measurement">Argentine</a></li> <li><a href="/wiki/Bolivian_units_of_measurement" title="Bolivian units of measurement">Bolivian</a></li> <li><a href="/wiki/Brazilian_units_of_measurement" title="Brazilian units of measurement">Brazilian</a></li> <li><a href="/wiki/Chilean_units_of_measurement" title="Chilean units of measurement">Chilean</a></li> <li><a href="/wiki/Colombian_units_of_measurement" title="Colombian units of measurement">Colombian</a></li> <li><a href="/wiki/Paraguayan_units_of_measurement" title="Paraguayan units of measurement">Paraguayan</a></li> <li><a href="/wiki/Peruvian_units_of_measurement" title="Peruvian units of measurement">Peruvian</a></li> <li><a href="/wiki/Uruguayan_units_of_measurement" title="Uruguayan units of measurement">Uruguayan</a></li> <li><a href="/wiki/Venezuelan_units_of_measurement" title="Venezuelan units of measurement">Venezuelan</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Ancient</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ancient_Arabic_units_of_measurement" title="Ancient Arabic units of measurement">Arabic</a></li> <li><a href="/wiki/Biblical_and_Talmudic_units_of_measurement" title="Biblical and Talmudic units of measurement">Biblical and Talmudic</a></li> <li><a href="/wiki/Ancient_Egyptian_units_of_measurement" title="Ancient Egyptian units of measurement">Egyptian</a></li> <li><a href="/wiki/Ancient_Greek_units_of_measurement" title="Ancient Greek units of measurement">Greek</a></li> <li><a href="/wiki/Hindu_units_of_time" title="Hindu units of time">Hindu</a></li> <li><a href="/wiki/History_of_measurement_systems_in_India" title="History of measurement systems in India">Indian</a></li> <li><a href="/wiki/Ancient_Mesopotamian_units_of_measurement" title="Ancient Mesopotamian units of measurement">Mesopotamian</a></li> <li><a href="/wiki/Persian_units_of_measurement" title="Persian units of measurement">Persian</a></li> <li><a href="/wiki/Ancient_Roman_units_of_measurement" title="Ancient Roman units of measurement">Roman</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">List articles</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_humorous_units_of_measurement" title="List of humorous units of measurement">Humorous</a></li> <li><a href="/wiki/List_of_obsolete_units_of_measurement" title="List of obsolete units of measurement">Obsolete</a></li> <li><a href="/wiki/List_of_unusual_units_of_measurement" title="List of unusual units of measurement">Unusual</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Absolute_scale" title="Absolute scale">Absolute scale</a></li> <li><a href="/wiki/N-body_units" title="N-body units">N-body</a></li> <li><a href="/wiki/Modulor" title="Modulor">Modulor</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style 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