The Web Content Accessibility Guidelines (WCAG)

The Web Content Accessibility Guidelines (WCAG) is the international accessibility standard established by the World Wide Web Consortium (W3C).

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What are the Web Content Accessibility Guidelines (WCAG)?

The Web Content Accessibility Guidelines (WCAG) is an international standard that was and continues to be, developed by the Web Accessibility Initiative (WAI), a part of the World Wide Web Consortium (W3C). The WCAG was created with the intention of making the web a more accessible place for people with disabilities.

The guidelines offer technical recommendations on how to make website content accessible. The guidelines are also the standard reference for most website accessibility-related legislation like the Americans with Disability Act (ADA) in the US, and the European Web Accessibility Directive.

While the WCAG is not enforceable, the guidelines have become the foundation of mandatory accessibility regulations around the world. For example, Section 508, AODA, CVAA, and the Australian DDA are based on WCAG 2.0 Level A and AA success criteria. In addition, the EU Web Accessibility Directive now requires compliance with WCAG 2.1 Level A and AA.

WCAG versions 2.0, 2.1, 2.2, and 3.0

The WCAG has gone through several updates since the publication of 1.0 in 1995. WCAG 1.0 has since been superseded by WCAG 2.0 and its subsequent versions.

  • WCAG 2.0 - published 11 December 2008.
  • WCAG 2.1 - published on 5 June 2018 and is now the W3C recommended version.
  • WCAG 2.2 - published on October 5th 2023.

The introduction of the new iterations adds new requirements.

  • WCAG 2.0 had 61 success criteria.
  • WCAG 2.1 introduced 17 more success criteria to address mobile accessibility, people with low vision, and people with cognitive and learning disabilities.
  • WCAG 2.2 expands on 2.1 with nine new success criteria, plus an update to one, with the goal of making content more accessible to a wider range of users.

The newer versions of WCAG 2 are backward compatible, meaning that all requirements in 2.0 are included in 2.1 and 2.2. So all content that conforms with the latest version of the guidelines should conform with the older versions too.

The current standing WCAG versions 2.0 and 2.1 are categorized according to four principles, perceivable, operable, understandable, and robust (POUR).

Elements that convey information, or website user interface components must be presented in a way that users are able to find, process, and understand.

All functionality and navigation on the website should be usable.

Information and the operation of the user interface must be clear and understandable to users of all abilities.

The website should be capable of adapting and developing itself to support a variety of current and potential future user agents, including assistive technologies.

Under each principle are testable success criteria that provide recommendations on how to make digital content more accessible. The success criteria are classified by three levels — A, AA, and AAA — with A being the most basic level of WCAG compliance, and AAA being the strictest.

Learn more about the elements of WCAG and how to comply with its success criteria.

On 21 January 2021, the WAI released the first working draft of the WCAG 3.0. WCAG 3.0 is planned to be a major revision with the intention to make the guidelines more user-friendly than the WCAG 2 iterations, and more flexible, covering even more content, apps, and tools, as well as organizations and disabilities. WCAG 3.0 is still in development and is not expected to be finalized for the next few years.

The difference between WCAG A, WCAG AA, and WCAG AAA compliance levels

The WCAG categorizes its conformance based on three levels: A, AA, and AAA. To be WCAG compliant, it is a requirement that one of these WCAG levels should be fully met.

Minimal WCAG compliance (level A)

Level A is the minimum level of conformance with criteria involving basic requirements that do not really impact the design or structure of the website.

Examples of Level A success criteria:

  • All non-text content like audio or video must have a text alternative, like alt text or captions, that serves the equivalent purpose.
  • Users can navigate the website effectively using only a keyboard
  • If there is audio that auto-plays on your website for more than three seconds, ensure that you provide means of adjusting the volume, stopping, or pausing it.
  • Offer an alternative (such as an audio track) for time-based media or video content.

Acceptable WCAG compliance (level AA)

Level AA is usually the level of compliance that is referred to by most accessibility laws that have adopted the WCAG. Level AA requires more commitment and technical intervention but results in a well-functioning, accessible site.

Examples of Level AA success criteria:

  • Provide descriptive headings and labels in content.
  • Navigational elements on the site, like menus, should be in a consistent, repeated position across the website.
  • When executing an action on the site, like filling in forms or clicking on buttons, errors can occur on the user’s part. If an error should occur, suggestions for correction should be provided.

Optimal WCAG compliance (level AAA)

Level AAA is the level for optimal conformance, but because of the more stringent and detailed technical requirements, many sites aren’t at this level.

Examples of Level AAA success criteria:

  • The visual presentation of text, and images of text, must have a contrast ratio of at least 7:1.
  • Remove timing limitations from all content, unless it is for non-interactive synchronized media and real-time events.
  • When a user has to submit information on a webpage, the submissions must be reversible, checked for input errors (and offer suggestions for correction if errors do occur), and a confirmation mechanism is in place to allow the user to review the submission and edit if needed.
  • Images of text should be avoided or only used for decoration.

WCAG 2.1 success criteria

The WCAG 2.1, which debuted in 2018, defined 17 additional success criteria. Following are some of the specific guidelines included in the updated WCAG levels:

WCAG 2.1 Level A success criteria

Examples of Level A success criteria:

  • Captions should be provided for pre-recorded audio content, except when the audio is a text alternative and is labeled as such.
  • When the sequence of content is essential to its meaning (such as content that spans several columns on a page), the reading sequence must be programmatically defined.
  • Color must not be the only visual means of conveying information or prompting an action (such as green buttons with no text that indicates they should be selected as a ‘yes’ response).
  • If a keyboard interface allows a user to move to a component of a page, that component must also allow the user to move away from it using only a keyboard interface, or the page must provide instructions for moving the focus away.

WCAG 2.1 Level AA success criteria

Examples of Level AA success criteria:

  • Content display is not restricted to portrait or landscape orientation, unless a specific display orientation is essential.
  • Text on a webpage (except for captions, and images of text) can be resized up to 200% without assistive technology and without loss of content or functionality.
  • Headings and labels describe topics or purpose.
  • Navigational elements repeated across or within a set of web pages occur in the same relative order, unless the user initiates a change.

WCAG 2.1 Level AAA success criteria

Examples of Level AAA success criteria:

  • All pre-recorded audio content has sign language interpretation.
  • Users can suppress or postpone interruptions, except for emergency interruptions.
  • A mechanism is available for identifying the meaning of or expanded form of abbreviations.
  • A mechanism is available for identifying the meaning of idioms, jargon, and words or phrases used in an unusual way.

Who should comply with the WCAG?

The WCAG was intended as a guideline for:

  • Web content developers (page authors, site designers, etc.)
  • Web authoring tool developers
  • Web accessibility evaluation tool developers

However, as the need for website accessibility grows, it is evident that anyone who has an online presence should use it as a standard for web accessibility. This includes policymakers, managers, researchers, educators, marketers, and communicators. Also, most international legislation references WCAG 2.0 level AA as the minimum web accessibility compliance, so many countries around the world have made it a requirement for anyone who owns a website to comply with these guidelines.

Benefits of complying with WCAG guidelines

Companies that comply with WCAG guidelines offer a better experience not just for users with disabilities, but for all website visitors. For example, logical navigation, and high contrast between text and background colors can help users of all abilities have better interactions with websites.

Other benefits of complying with WCAG guidelines include:

Reducing legal risk — While WCAG guidelines cannot be enforced, they do influence other enforceable regulations. Being compliant with WCAG should help companies avoid violating accessibility-related regulations.

Improving search relevance — A website that is truly accessible to all users is also fully accessible to search engine bots. These bots — bits of software that crawl websites — don’t see all content as humans would, so any additional context that helps bots evaluate the relevance of content can help improve a website’s search engine rankings.

Reaching new audiences — Approximately 15% of the world’s population has some type of disability. When you make your website accessible, you’re welcoming countless new visitors and tapping into potential new revenue streams.

How to check your website’s WCAG compliance level

Web accessibility is a non-negotiable aspect of user experience, and with the WCAG being the most established standard for accessibility guidelines, you should ensure that you and your organization are taking the necessary steps to bring your website into compliance.

There are a few ways you can approach web accessibility testing and remediation. First, review the WCAG reference guide. It breaks down each recommendation, providing context about its intent, as well as examples of success techniques and failures. This guide is a good starting point for achieving WCAG compliance.

Another way to review your site for WCAG compliance is to employ an automated testing tool that can audit your site and identify accessibility issues. Monsido offers a dashboard that keeps track of your accessibility levels based on the issues that you have addressed. But like all automated tools, you will need manual testing.

Monsido can find your issues, and even fix some basic ones automatically, but we always advocate for manual review and remediation. While automated tools can help you find the issues, web accessibility is all about users, so you need real user testing and validation to ensure accessibility.

How Monsido can help your website meet WCAG standards

Monsido’s Web Accessibility Module audits your entire site for accessibility against the WCAG 2.0 and 2.1 (and any subsequent updates to the guidelines).

Each audit scans your site for machine-testable issues, provides detailed reports so you can review any errors that may arise, gives you targeted recommendations on how to address these errors based on the guidelines, and shows you your compliance based on levels A, AA, and AAA. You can track and prove your accessibility compliance progress via reports in the History Center. We also offer accessibility training to customers and support, all-inclusive, to ensure that you are well-versed in both automated and manual remediation methods, and can efficiently and consistently improve your website’s accessibility.

Monsido also offers free tools to complement your web accessibility efforts, including a color contrast checker for web teams to test out compliant color combinations for their web design, and an accessibility statement generator, which helps you generate a public statement declaring your commitment to web accessibility and helps make your web accessibility policy transparent to all your users.

Frequently Asked Questions

Is WCAG 2.1 a legal requirement?

WCAG 2.1 is currently not enforceable, but other regulations may require websites to comply with its recommendations.

Is WCAG 2.0 still valid?

So far, each iteration of the WCAG is backward-compatible, meaning that previous versions — including WCAG 2.0 — are still applicable.

How will WCAG revisions affect compliance?

WCAG 2.2 is expected to be published in 2021. While the new 2.2 criteria are still in draft version, businesses that are already in compliance with WCAG 2.1 should be well prepared to comply with the newest version.

How do you test WCAG compliance?

The best way to test WCAG compliance is with software and human expertise. Software can catch some of the most common website accessibility errors, but a professional review of accessibility diagnostics is always recommended.

Learn more about how Monsido helps websites anticipate and comply with accessibility guidelines.


The information in this article is made available by Acquia Inc. and/or its subsidiaries and affiliates and is for informational purposes only so as to provide its customers with a general understanding of current legal developments. It should not be construed as providing specific legal advice, and you acknowledge that no attorney/client relationship exists between you or any third party and Acquia Inc. and/or its subsidiaries and affiliates. This article should not be used as a substitute for competent legal advice from a licensed lawyer in your jurisdiction.

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