CINXE.COM

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>WebAIM: Web Content Accessibility Guidelines</title> <link rel="shortcut icon" href="/media/favicon.ico"> <link rel="home" href="/"> <link rel="search" href="/search/"> <link rel="alternate" href="https://webaim.org/blog/feed" type="application/rss+xml" title="WebAIM Blog"> <script async src="https://www.googletagmanager.com/gtag/js?id=G-Y41PF8WV9X"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-Y41PF8WV9X'); </script> <link href="/styles/main.css" rel="stylesheet" type="text/css"> <link href="/styles/print.css" rel="stylesheet" type="text/css" media="print"> <script src="/media/scripts/jquery.js"></script> <script src="/media/scripts/main.js"></script> <link href='https://fonts.googleapis.com/css?family=Roboto:400' rel='stylesheet' type='text/css'> <link href='https://fonts.googleapis.com/css?family=Kameron:400,700' rel='stylesheet' type='text/css'> <link href="/styles/documents.css?ver=2" rel="stylesheet"> <link href="https://fonts.googleapis.com/css?family=Open+Sans:400,400i,700" rel="stylesheet">  </head> <body> <div id="headcontainer" class="clearfix" style="background-image: url(/media/banners/articles.jpg)"> <header> <div id="skiptocontent"><a href="#maincontent">skip to main content</a></div> <h2><a href="/"><img src="/media/logo.png" width="315" height="83" alt="WebAIM - Web Accessibility In Mind"></a></h2> <nav> <h2 class="hidden">Main Navigation</h2> <ul> <li><a href="/services/">Services</a></li> <li class="current"><a href="/articles/">Articles</a></li> <li><a href="/resources/">Resources</a></li> <li><a href="/projects/">Projects</a></li> <li><a href="/community/">Community</a></li> </ul> </nav> <div id="search"> <form method="get" role="search" action="/search/" id="sitesearch"> <p class="search"><span><label for="q">Search:</label> <input type="text" name="q" id="q"><input type="image" src="/media/template/search.svg" alt="Submit Search"></span></p> </form> <p class="intro"><a href="/intro">Introduction to Web Accessibility</a></p> <p class="training"><a href="/services/training">WebAIM Training</a></p> </div> </header> </div> <main id="maincontainer" class="clearfix"> <article id="maincontent"> <h1>Web Content Accessibility Guidelines</h1> <p id="breadcrumbs"><span class="hidden">You are here: </span><a href="/">Home</a> > <a href="/articles/">Articles</a> > The Web Content Accessibility Guidelines</p> <nav role="navigation"> <h2>Article Contents</h2> <ol> <li><a href="#background">Background</a></li> <li><a href="#current">The Current Standard</a></li> <li><a href="#future">The Future</a></li> </ol> </nav> <div class="callout"> <div class="title">WebAIM Accessibility Testing Services</div> <p>The experts at WebAIM can audit your web site and provide a detailed report to help you remediate accessibility and WCAG compliance issues.</p> <p class="calloutlink"><a href="/services/evaluation">Learn more about WebAIM Evaluation Services</a> </div> <div class="note"> <div class="title">NOTE:</div> <p>A <a href="checklist">WCAG 2 Checklist</a> is available for developers to use in implementiation and verification of conformance.</p> </div> <div class="section" id="background"> <h2>Background</h2> <h3>The W3C's Web Accessibility Initiative</h3> <p><img src="media/w3c-wai.png" alt="Web Accessibility Initiative logo" class="floatright"> The W3C is an international, vendor-neutral group that determines protocols and standards for the web. Within the W3C, the <a href="//www.w3.org/WAI/">Web Accessibility Initiative (WAI)</a> and its <a href="//www.w3.org/WAI/groups.html">working groups</a> develop accessibility guidelines for web browsers, authoring tools, evaluation tools, and web content, to name a few. The <a href="//www.w3.org/WAI/GL/">Accessibility Guidelines Working Group</a> creates guidelines called the <a href="//www.w3.org/WAI/standards-guidelines/wcag/">Web Content Accessibility Guidelines (WCAG)</a>.</p> <h3>WCAG 1.0</h3> <p>WCAG 1.0, finalized in 1999, was a major development in making web content more accessible to people with disabilities. Its 14 guidelines and numerous checkpoints formed the basis for the initial <a href="/articles/laws/usa/rehab#s508">Section 508</a> guidelines.</p> <p>As technologies advanced, WCAG 1.0 became less relevant, and the development of WCAG 2.0 began.</p> <h3>WCAG 2.0</h3> <p>WCAG 2.0, released in 2008, shifted emphasis from technique-centered checkpoints to guidelines and success criteria rooted in four core principles:</p> <ul> <li>Perceivable</li> <li>Operable</li> <li>Understandable</li> <li>Robust</li> </ul> <p>These principles (sometimes referred to as "POUR") remain constant as technology changes. Each principle contains guidelines, which in turn contain various success criteria. The principles are examined in depth in <a href="/articles/pour/">Constructing a POUR Website</a>.</p></div> <div class="section" id="current"> <h2>The Current Standard: WCAG 2.2</h2> <p>WCAG 2 has been updated twice, to sub-versions 2.1 (in 2018) and 2.2 (in 2023). These sub-versions did not replace WCAG 2.0 in the same way that WCAG 2.0 replaced 1.0. Instead, each added new success criteria. Sub-version 2.1 notably added much in the area of mobile devices. The four core principles from 2.0 remain unchanged, as do most success criteria.</p> <h3>Levels of Conformance</h3> <p>To help development teams prioritize accessibility implementation and remediation efforts, WCAG success criteria are organized into three levels of conformance:</p> <ul> <li><b>Level A</b> is a basic requirement for some users with disabilities to be able to access and use web content.</li> <li><b>Level AA</b> indicates overall accessibility and removal of significant barriers to accessing content.</li> <li><b>Level AAA</b> provides improvements and enhancements to web accessibility for some users with disabilities.</li> </ul> <p>These levels are cumulative. To claim Level AA conformance, a website must meet all Level A and AA success criteria. Likewise, Level AAA conformance implies that all success criteria from all three levels have been met.</p> <p>Most websites should aim for Level AA conformance. Depending on the target users, some Level AAA success criteria such as <a href="/standards/wcag/checklist#sc3.1.5">Reading Level, <a href="/standards/wcag/checklist#sc1.4.6">Contrast (Enhanced), <a href="/standards/wcag/checklist#sc2.5.5">Target Size</a>, or others may be beneficial to implement. Very few websites can claim full Level AAA conformance鈥攏ot even webaim.org or the WCAG website itself!</p> <h3>Conformance Claims</h3> <p>The W3C-WAI outlines a recommended process to <a href="//www.w3.org/WAI/WCAG21/Understanding/conformance">claim conformance</a> to one of the levels above. This optional process is based on self-assessment and does not imply certification by the W3C. Third-party organizations like WebAIM can also <a href="/services/evaluation/">evaluate a website</a> and <a href="/services/certification/example">certify conformance</a>.</p> </div> <div class="section" id="future"> <h2>The Future</h2> <h3>WCAG 2.<i>n</i></h3> <p>WCAG 2 continues to be updated. Additional success criteria are being developed for a future <a href="/blog/wcag-2-2-overview-and-feedback/">WCAG 2.2</a> and further sub-versions of WCAG 2.</p> <h3>The Silver Project</h3> The Silver Task Force grew out of the early WCAG 2.1 project, because a group of people wanted to work on the next major evolution of accessibility guidance using a user experience model. This meant <a href="https://docs.google.com/presentation/d/1POs7orJ4ALB0bq5_vyo4v8RxDcr-5ctwD1noVgpXuJc/edit#slide=id.gc6f73a04f_0_9">researching</a> what users needed from accessibility guidance and potentially recommending a major restructuring for WCAG 3.0.</p> </article>  <aside id="articlemeta"> <div id="updated">Last updated: <time datetime="2020-09-21">Sep 21, 2020</time></div> <div id="related"> <h2>Related Resources</h2> <ul> <li><a href="/standards/wcag/checklist">WCAG 2 Checklist</a></li> <li><a href="/articles/pour/">Constructing a POUR Website</a></li> </ul> </div> </aside> </main> <footer> <div id="footerresources"> <div class="footerblock"> <h2 id="copyright">©2025 WebAIM</h2> <p id="contact"> Utah State University<br> 6807 Old Main Hill<br> Logan, UT 84322-6807<br> <a class="phone" href="tel:4357977024">435.797.7024</a></p> <div id="checkpage"> <h2>Check Your Accessibility</h2> <form action="https://wave.webaim.org/report" novalidate> <label for="waveurl">Web site address:</label> <input type="url" id="waveurl" name="url" title="Web site address"> <input type="submit" value="WAVE"> </form> </div> </div> <div class="footerblock"> <h2 id="blog">From the Blog</h2> <ul><li><a href="/blog/salary-survey-results/">Global Digital Accessibility Salary Survey Results</a></li><li><a href="/blog/join-the-discussion/">Join the Discussion鈥擣rom Your Inbox</a></li><li><a href="/blog/severity-ratings/">Using Severity Ratings to Prioritize Web Accessibility Remediation</a></li><li><a href="/blog/25-tips/">25 Accessibility Tips to Celebrate 25 Years</a></li></ul> </div> <div class="footerblock"> <h2 id="popular">Popular Resources</h2> <ul> <li><a href="/training/virtual">WebAIM Training</a></li> <li><a href="/standards/wcag/checklist">WCAG 2 Checklist</a></li> <li><a href="/newsletter">WebAIM Monthly Newsletter</a></li> <li><a href="/resources/contrastchecker">Color Contrast Checker</a></li> <li><a href="/resources/designers/">Web Accessibility for Designers</a></li> <li><a href="http://wave.webaim.org/">WAVE Web Accessibility Evaluation Tool</a></li> </ul> </div> <div id="footerlinks"> <ul> <li><a id="footercontact" href="/contact">Contact</a></li> <li><a id="footerabout" href="/about">About</a></li> <li><a id="footerrss" href="/community/rss">RSS Feeds</a></li> <li><a id="footertwit" href="http://twitter.com/webaim">Twitter</a></li> <li><a id="footercopyright" href="/copyright">Copyright & Terms of Use</a></li> </ul> </div> <div class="clear"></div> </div> </footer> </body> </html>