Web Content Accessibility Guidelines (WCAG) Overview

Introduction

Web Content Accessibility Guidelines (WCAG) is developed through the W3C process in cooperation with individuals and organizations around the world, with a goal of providing a single shared standard for web content accessibility that meets the needs of individuals, organizations, and governments internationally.

The WCAG documents explain how to make web content more accessible to people with disabilities. Web “content” generally refers to the information in a web page or web application, including:

• natural information such as text, images, and sounds
• code or markup that defines structure, presentation, etc.

WCAG 2.0, 2.1, 2.2

WCAG 2.0 was published on 11 December 2008.
WCAG 2.1 was published on 5 June 2018.
WCAG 2.2 is scheduled to be published in 2021.

All requirements (“success criteria”) from 2.0 are included in 2.1. The 2.0 success criteria are exactly the same (verbatim, word-for-word) in 2.1.
All requirements in 2.0 and 2.1 will be included in 2.2. The wording of the 2.0 and 2.1 success criteria will be exactly the same in 2.2.

There are additional success criteria in 2.1 that are not in 2.0. They are introduced in What’s New in WCAG 2.1.
The proposed new success criteria in 2.2 are introduced in What’s New in WCAG 2.2 Working Draft.

Content that conforms to WCAG 2.1 also conforms to WCAG 2.0.
And content that conforms to WCAG 2.2 will also conform to 2.1 and 2.0. (This is often called “backwards compatible”.) A website that meets WCAG 2.1 or 2.2 should meet the requirements of policies that reference WCAG 2.0. To put it another way: If you want to meet both WCAG 2.0 and WCAG 2.1, you can use the 2.1 resources and you don’t need to bother looking at 2.0.

WCAG 2.0 and WCAG 2.1 are both existing standards. WCAG 2.1 does not deprecate or supersede WCAG 2.0. W3C encourages you to use the most recent version of WCAG when developing or updating content or accessibility policies.

Who WCAG is for

WCAG is primarily intended for:

• Web content developers (page authors, site designers, etc.)
• Web authoring tool developers
• Web accessibility evaluation tool developers
• Others who want or need a standard for web accessibility, including for mobile accessibility

Related resources are intended to meet the needs of many different people, including policy makers, managers, researchers, and others.

WCAG is a technical standard, not an introduction to accessibility. For introductory material, see “Where should I start?” in the FAQ.

What is in the WCAG 2 Documents

WCAG 2.0 and WCAG 2.1 are stable, referenceable technical standards. They have 12-13 guidelines that are organized under 4 principles: perceivable, operable, understandable, and robust. For each guideline, there are testable success criteria, which are at three levels: A, AA, and AAA.

For a short summary of the WCAG 2 guidelines, see WCAG 2.1 at a Glance.

To learn about web accessibility principles and guidelines, see Accessibility Principles.

The WCAG 2 supporting technical materials include:

• How to Meet WCAG 2: A customizable quick reference to Web Content Accessibility Guidelines 2 requirements (success criteria) and techniques is essentially the WCAG 2 checklist. Most people use this quick references as the main resource for working with WCAG.
• Techniques for WCAG 2 (2.1 Techniques, 2.0 Techniques) gives you specific details on how to develop accessible web content, such as HTML code examples. The techniques are “informative”, that is, you do not have to use them. The basis for determining conformance to WCAG 2 is the success criteria from the WCAG 2 standard, not the techniques. Read more in Techniques in the FAQ.
• Understanding WCAG 2 (2.1 Understanding, 2.0 Understanding) has additional guidance on learning and implementing WCAG 2 for people who want to understand the guidelines and success criteria more thoroughly.

For more details on how these document are related and how they are linked, see WCAG 2 Documents.

Translations

Authorized Translations and unofficial translations of WCAG 2 are listed in WCAG 2 Translations.

Technical document format

The WCAG, Techniques, and Understanding documents follow the W3C format for technical reports, which has several sections at the beginning, including links to different versions, editors, abstract, and status.

Supplemental guidance

Supplemental guidance provides additional information beyond what is required in WCAG 2.0 and 2.1. It addresses improving accessibility for people with cognitive disabilities and people with low vision. Links to supplemental guidance will be added to this section in the future.

WCAG 2.0 is ISO/IEC 40500

WCAG 2.0 is approved as an ISO standard: ISO/IEC 40500:2012. ISO/IEC 40500 is exactly the same as the original WCAG 2.0, which is introduced above along with supporting resources.

The content of ISO/IEC 40500 is freely available from www.w3.org/TR/WCAG20; it is available for purchase from the ISO catalogue .

Benefits of WCAG 2.0 as an ISO standard are summarized in ISO in the FAQ. More information on W3C and the ISO process is in the W3C PAS FAQ.

Other guidelines

WCAG is part of a series of accessibility guidelines, including the Authoring Tool Accessibility Guidelines (ATAG) and the User Agent Accessibility Guidelines (UAAG). Essential Components of Web Accessibility explains the relationship between the different guidelines.

Who develops WCAG

The WCAG technical documents are developed by the Accessibility Guidelines Working Group (AG WG) (formerly the Web Content Accessibility Guidelines Working Group), which is part of the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI).

WAI updates Techniques for WCAG 2 and Understanding WCAG 2 periodically. We welcome comments and submission of new techniques.

Opportunities for contributing to WCAG and other WAI work are introduced in Participating in WAI.

More Information

See the WCAG 2 FAQ for more information on:

• WCAG 2 coverage of mobile accessibility
• WCAG 2 applicability to non-W3C technologies
• WCAG 3.0 (“Silver”)
• and more…