WCAG: What It Is, Who Writes It, and Which Version You Need

WCAG stands for Web Content Accessibility Guidelines. It is a technical standard published by the World Wide Web Consortium (W3C) that defines, in testable terms, what makes digital content usable by people with disabilities. There are three versions in use - 2.0 (2008), 2.1 (2018) and 2.2 (2023) - and three conformance levels: A, AA and AAA. WCAG 2.1 Level AA is what nearly every law, contract and procurement document asks for. WCAG is not itself a law; it becomes binding when legislation references it, which most digital accessibility legislation now does.

Who creates WCAG?

WCAG is written by the Accessibility Guidelines Working Group (AG WG), part of the W3C's Web Accessibility Initiative (WAI). The W3C is the international standards body for the web, directed by its member organisations, and WAI is the part of it dedicated to accessibility.

The working group is not a closed committee. It brings together browser vendors, assistive technology makers, universities, government agencies, disability organisations and accessibility practitioners, and its drafts are published publicly for comment before they advance. A guideline only becomes a W3C Recommendation - the final, ratified status - after that public review process and a formal member vote.

This is why WCAG carries the weight it does: it is a consensus standard produced in the open, not a vendor specification, which is what makes it safe for legislators to reference.

The versions, and which one applies to you

Each version is a superset of the one before. Content that meets WCAG 2.2 automatically meets 2.1 and 2.0.

Version	Published	Success criteria	Where it is referenced
WCAG 2.0	11 December 2008	61	Section 508 (US federal), AODA (Ontario)
WCAG 2.1	5 June 2018	78	EN 301 549 (EU), ADA Title II rule (US state and local government)
WCAG 2.2	5 October 2023	86	The current W3C Recommendation; expected in the next round of regulatory updates

Explore the WCAG library

WCAG 2.1 The version most laws point at. The 4 principles, the three levels, and the 17 success criteria that arrived with 2.1. Read the guide WCAG 2.2 The current Recommendation: focus appearance, dragging alternatives, target size at AA and accessible authentication. Read the guide WCAG compliance What "WCAG compliant" actually means, which level the law expects, and the steps from failing to documented. Read the guide WCAG testing Automated vs manual testing, the step-by-step process, and how results become audit-grade evidence. Read the guide All 86 success criteria Every WCAG 2.2 success criterion in plain English - filter by level, version and principle, with how-to-meet notes. Browse the criteria WCAG for PDFs How the criteria apply to documents, where PDF/UA fits, and how to test and remediate a PDF library. Read the guide Accessibility Wiki 217 scanner rules explained in plain language - 135 for the web, 82 for PDF/UA - each with why it matters, the fix, and the WCAG criterion it maps to. Open the wiki Get a full WCAG audit Certified IAAP/CPWA specialists test criterion by criterion and document the result. See how audits work

Levels A, AA and AAA

The three conformance levels are cumulative. Level AA includes everything in Level A; Level AAA includes everything in both.

Level A is the minimum. A failure here usually means some people cannot complete a task at all - a video with no captions, a control that cannot be reached by keyboard.
Level AA is the working standard. It is what EN 301 549, the ADA Title II rule and virtually every accessibility clause in a contract require.
Level AAA is an enhancement. The W3C explicitly advises against requiring AAA across a whole site, because some content cannot meet it.

How WCAG is organised

Every requirement in WCAG sits under one of four principles, known by the acronym POUR: content must be Perceivable, Operable, Understandable and Robust. Under the principles sit guidelines, which are broad goals, and under those sit the success criteria - the individual, testable pass-or-fail statements that an audit actually checks. You can browse every one of them, in plain English, in the criteria library.

Only the success criteria are normative. The W3C also publishes two large supporting documents, Understanding WCAG and Techniques for WCAG, which explain intent and show ways to meet each criterion. Those are advisory: when a law references WCAG, it is the success criteria that bind.

Frequently asked questions

What does WCAG stand for?

Web Content Accessibility Guidelines. It is usually pronounced "wuh-cag".

Who creates the Web Content Accessibility Guidelines?

The Accessibility Guidelines Working Group within the W3C's Web Accessibility Initiative (WAI), through an open, public consensus process that ends in a formal W3C Recommendation.

Is WCAG a law?

No. WCAG is a technical standard. It becomes legally binding where a law or contract references it - as EN 301 549 and the US ADA Title II rule both do.

What is WCAG compliance?

Meeting every success criterion at a stated conformance level, on the pages you are claiming for. In practice "WCAG compliance" almost always means WCAG 2.1 or 2.2 at Level AA.

Which WCAG version should I target?

WCAG 2.2 Level AA. It is backwards compatible, so it satisfies every regulation that currently references 2.0 or 2.1.

How many success criteria are there?

61 in WCAG 2.0, 78 in WCAG 2.1 and 86 in WCAG 2.2.

Sources

W3C Web Accessibility Initiative, WCAG 2 Overview - w3.org/WAI
W3C, Web Content Accessibility Guidelines (WCAG) 2.2, W3C Recommendation - w3.org/TR/WCAG22
W3C, How WAI Develops Accessibility Standards - w3.org/WAI

Last updated 12 August 2026. Reviewed by the EqualWeb accessibility team.

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