WCAG 2 Overview

Introduction

Web Content Accessibility Guidelines (WCAG) 2 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.

Who WCAG is for

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

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

To meet the needs of others — including policy makers, managers, and researchers — there are many different WAI Resources.

What is in WCAG 2

The WCAG 2.2 has 13 guidelines. The guidelines are organized under 4 principles: perceivable, operable, understandable, and robust.

For each guideline, there are testable success criteria. The success criteria are at three levels: A, AA, and AAA.

The success criteria are what determine “conformance” to WCAG. That is, in order to meet WCAG, the content needs to meet the success criteria. Details are in the Conformance section of WCAG.

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

Supporting material and supplemental guidance

The following resources help you understand and implement WCAG, and improve accessibility beyond WCAG:

• Quick Reference / How to Meet WCAG 2 / Checklist
• Understanding WCAG 2
• Techniques for WCAG 2
• Test Rules for WCAG 2
• Supplemental Guidance

Please read about these WCAG 2 resources from WCAG 2 Documents.

WCAG 2.0, 2.1, 2.2

The Web Content Accessibility Guidelines (WCAG) standards are stable and referenceable when they are published as a ‘W3C Recommendation’ web standard.

• WCAG 2.0 was published on 11 December 2008.
• WCAG 2.1 was published on 5 June 2018, and an update was published on 21 September 2023. The WCAG 2 FAQ has information about the update.
• WCAG 2.2 was published on 5 October 2023.

WCAG 2.0, 2.1, and 2.2 are designed to be “backwards compatible”, which means content that conforms to WCAG 2.2 also conforms to WCAG 2.1 and WCAG 2.0. If you want to meet all the versions, you can use the WCAG 2.2 resources and you don’t need to bother looking at earlier versions.

All the success criteria from 2.0 are included in 2.1, and all from 2.1 are in 2.2 (except 4.1.1, explained in the next paragraph).

• WCAG 2.0 has 12 guidelines.
• WCAG 2.1 adds 1 guideline and 17 success criteria. They are introduced in What’s New in WCAG 2.1.
• WCAG 2.2 adds 9 success criteria. They are introduced in What’s New in WCAG 2.2.

A few things have changed, and we intend the updates in the related documents to support backwards compatibility in practice. The main change is that in WCAG 2.2, one success criteria (4.1.1 Parsing) is obsolete. Notes added to WCAG 2.1 and WCAG 2.0 errata address this, as explained in WCAG 2 FAQ, 4.1.1 Parsing. WCAG 2.2 also includes Notes about different languages; more information is in WCAG 2 FAQ, internationalization.

WCAG 2.0, WCAG 2.1, and WCAG 2.2 are all existing standards. WCAG 2.2 does not deprecate or supersede WCAG 2.1, and WCAG 2.1 does not deprecate or supersede WCAG 2.0. W3C encourages you to use the most recent version of WCAG.

Translations

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

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.

W3C plans to submit WCAG 2.2 through the ISO process.

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.

WCAG 3 and more information

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.

See the WCAG 2 FAQ for more information on:

• WCAG 2 coverage of mobile accessibility
• Applying WCAG 2 to documents and software
• and more…

For information on the early draft of W3C Accessibility Guidelines 3.0 (formerly known as “Silver”), see the WCAG 3 Introduction.