language: en · status: in-force · last checked: 2026-10-29

Web Content Accessibility Guidelines (WCAG) 2.0, 2.1 and 2.2

The W3C's technical standard for accessible web content: four principles (perceivable, operable, understandable, robust), guidelines under each, and testable success criteria at three conformance levels, A, AA and AAA (WCAG 2.2, Conformance Level). Each version is a separate W3C Recommendation and each remains one; later versions add success criteria, and 2.2 also removes one (4.1.1 Parsing, WCAG-2-2.md#parsing). WCAG is not law, but laws and harmonised standards incorporate a named version, so the corpus holds all three, each at the edition the law cites.

Applicability to EdTech

WCAG is what an accessibility obligation on a school's web content, apps and documents is measured against, and so what a supplier's conformance report (a VPAT/ACR) is written against. Which version applies depends on the instrument:

• US public schools: WCAG 2.1 AA under the ADA Title II rule. A public entity's web content and mobile apps, including those it provides "directly or through contractual, licensing, or other arrangements", must "comply with Level A and Level AA success criteria and conformance requirements specified in WCAG 2.1" from 26 April 2027 or 2028 depending on population (REQUIREMENTS.md#p-35-200-b-1). The rule defines WCAG 2.1 as the "W3C Recommendation 05 June 2018" (DEFINITIONS.md#section-35-104), the edition reproduced here.
• "Section 508 compliant": WCAG 2.0 AA. The Revised 508 Standards require electronic content to "conform to Level A and Level AA Success Criteria and Conformance Requirements in WCAG 2.0" (SECTION-508-STANDARDS.md#p-E205-4), and software likewise (SECTION-508-STANDARDS.md#p-E207-2). These bind federal agencies; K-12 RFPs borrow them.
• Europe and the UK: through EN 301 549. The harmonised standard's web clauses each require a web page to "satisfy WCAG 2.2 Success Criterion" so-and-so, and it states the equivalence: "Conformance with W3C Web Content Accessibility Guidelines (WCAG 2.2) [4] Level AA is equivalent to conforming with all of clauses 9.1 to 9.4 and with the conformance requirements of clause 9.6 of the present document" (WEB.md#clause-9-0). It gives the partial equivalences for WCAG 2.0 and 2.1 in the same clause. That is V4.1.1. The Web Accessibility Directive's presumption of conformity rests on V3.2.1 and WCAG 2.1 until the Official Journal cites the new version (see the EN 301 549 README).

The success criteria mostly speak of "web pages", but the standards that adopt them carry them over to non-web documents and software by word substitution: the 508 Standards' E205.4.1 and E207.2.1 (SECTION-508-STANDARDS.md), and EN 301 549 clauses 10 and 11 (NON-WEB-DOCUMENTS.md, NON-WEB-SOFTWARE.md).

Contents

Every success criterion is anchored by W3C's own fragment id, so a corpus link opens the same place on w3.org: Success Criterion 1.1.1 is WCAG-2-2.md#non-text-content in 2.1 and 2.2 and WCAG-2-0.md#text-equiv-all in 2.0, whose ids differ. The informative Introduction, the change logs and the W3C's supporting documents (Understanding WCAG, Techniques, the Quick Reference) are not reproduced.

Versions

• 2.2 extends 2.1. W3C's Introduction to 2.2 says: "WCAG 2.2 builds on and is backwards compatible with WCAG 2.1, meaning web pages that conform to WCAG 2.2 are at least as accessible as pages that conform to WCAG 2.1." and "WCAG 2.2 has removed one success criterion, 4.1.1 Parsing. Authors that are required by policy to conform with WCAG 2.0 or 2.1 will be able to update content to WCAG 2.2, but may need to continue to test and report 4.1.1." (WCAG 2.2, Comparison with WCAG 2.1). It names the nine new criteria and adds: "The Accessibility Guidelines Working Group recommends that sites adopt WCAG 2.2 as their new conformance target, even if formal obligations mention previous versions" (New Features in WCAG 2.2).
• Numbering is stable. New criteria are appended to their guideline, "but it means success criteria in each guideline are no longer grouped by conformance level" (Numbering in WCAG 2.2), so read the level printed on each criterion.
• 2.1 has later editions with errata. W3C re-issued WCAG 2.1 as a Recommendation on 21 September 2023, 12 December 2024 and 06 May 2025; the last is what https://www.w3.org/TR/WCAG21/ now serves. Its change log records, among editorial fixes, that the definitions of "single pointer", "used in an unusual or restricted way" and "programmatically determined link context" were modified (WCAG 2.1 (2025), Change Log). The corpus reproduces the 05 June 2018 edition because that is the one the ADA rule and EN 301 549 V3.2.1 cite; where a later definition matters, read it against the 2025 edition.
• ISO. EN 301 549 notes "WCAG 2.0 is identical to ISO/IEC 40500:2012" and "WCAG 2.2 is identical to ISO/IEC 40500:2025" (WEB.md#clause-9-0).

Licence

Each W3C page carries its copyright notice and links "document use" to the W3C Document License. The current version, which the links on all three pages resolve to (W3C Document License, 2023 version, read 2026-10-29; "in effect since 1 January 2023"), grants: "Permission to copy, and distribute the contents of this document, or the W3C document from which this statement is linked, in any medium for any purpose and without fee or royalty is hereby granted, provided that you include the following on ALL copies of the document, or portions thereof, that you use: A link or URL to the original W3C document. The pre-existing copyright notice of the original author […] If it exists, the STATUS of the W3C document." It continues: "No right to create modifications or derivatives of W3C documents is granted pursuant to this license", except in software and its documentation.

"For any purpose" includes commercial use, so the label is open-licence. How the corpus meets each condition: every document's first line, a {.meta} provenance line, links the dated W3C URL, reproduces that page's copyright notice verbatim (WCAG 2.2: "Copyright © 2020-2024 World Wide Web Consortium. W3C® liability, trademark and document use rules apply."; 2.1: "Copyright © 2017-2018 W3C® (MIT, ERCIM, Keio, Beihang). …"; 2.0: "Copyright © 2008 W3C® (MIT, ERCIM, Keio), All Rights Reserved. …") and gives the status ("W3C Recommendation 12 December 2024" and so on).

The curator's reading of the no-derivatives term, recorded per METHODOLOGY section 5: the corpus copies portions of each Recommendation word for word and does not modify them. Its builder's verify proves the reproduced words equal the source sections' words in order. Converting the markup to Markdown, dropping navigation links, and setting a printed label such as "Note 1" in bold before its text are presentation of the copied text, not a modified or derivative specification. If W3C took a different view, the fix would be to publish the pages unconverted, not to stop.

Related

• EN 301 549 — the European ICT accessibility standard; its clauses 9 to 11 apply WCAG 2.2 to web pages, non-web documents and software
• ADA Title II web rule — makes WCAG 2.1 AA the legal standard for US public entities, school districts included
• Section 504 / 508 — the Revised 508 Standards incorporate WCAG 2.0 AA
• EU Web Accessibility Directive — public-sector websites and apps, presumption of conformity through EN 301 549
• European Accessibility Act — products and services, the directive EN 301 549 V4.1.1 was prepared for
• PSBAR 2018 — the UK public-sector accessibility regulations

Sources

• Web Content Accessibility Guidelines (WCAG) 2.2, W3C Recommendation 12 December 2024
• Web Content Accessibility Guidelines (WCAG) 2.1, W3C Recommendation 05 June 2018
• Web Content Accessibility Guidelines (WCAG) 2.0, W3C Recommendation 11 December 2008
• WCAG 2.1, W3C Recommendation 06 May 2025 — the current 2.1 edition, cited for its change log, not reproduced
• W3C Document License, 2023 version