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WCAG explained: the Web Content Accessibility Guidelines

Updated October 14, 2026 · 4 min read

WCAG — the Web Content Accessibility Guidelines — is the international standard for accessible websites and apps. It is published by the W3C Web Accessibility Initiative and describes, in testable rules, what a page needs so that people with disabilities can use it: blind people with screen readers, people who cannot use a mouse, people with low vision, deaf people, people with cognitive disabilities.

The four principles

All success criteria are grouped under four principles, often abbreviated POUR:

  1. Perceivable — information can be seen or heard: text alternatives for images, captions for videos, enough contrast.
  2. Operable — everything works with a keyboard, there is enough time, nothing flashes dangerously, navigation is clear.
  3. Understandable — language is set, behaviour is predictable, forms explain errors.
  4. Robust — the code works with assistive technologies: every control has a name, a role and a state.

Levels A, AA and AAA

Each success criterion has a level. A is the minimum, AA adds what most users need, and AAA is the strictest. Laws and policies — EN 301 549 in the European Union, Section 508 and ADA settlements in the US — ask for level AA, which means all A and AA criteria. More in WCAG levels A, AA and AAA.

Versions: 2.0, 2.1, 2.2

WCAG 2.0 dates from 2008, 2.1 from 2018 and 2.2 from 2023. Each version keeps the earlier criteria and adds new ones; 2.2 also removed 4.1.1 Parsing. A site that meets 2.2 AA also meets 2.1 AA and 2.0 AA. What changed in each version: WCAG 2.1 vs 2.2.

All A and AA success criteria

The table lists the 55 success criteria of WCAG 2.2 at levels A and AA. Each one links to our explanation in plain words and to the official W3C text, and shows whether our automated checks test part of it.

22 of the 55 WCAG 2.2 success criteria of levels A and AA have at least one automated check in our library. The others are marked "manual review": a person has to check them.

Success criterion Level What the checker tests
1.1.1 Non-text Content W3C A Partly automated: Some gauges have no name, Some progress bars have no name, Images have no text description, An image button has no text description and 3 more (all rules)
1.2.1 Audio-only and Video-only (Prerecorded) W3C A Manual review
1.2.2 Captions (Prerecorded) W3C A Partly automated: Videos have no captions
1.2.3 Audio Description or Media Alternative (Prerecorded) W3C A Manual review
1.2.4 Captions (Live) W3C AA Manual review
1.2.5 Audio Description (Prerecorded) W3C AA Manual review
1.3.1 Info and Relationships W3C A Partly automated: The whole page is hidden from screen readers, Custom menus or lists are built incorrectly, Custom menu items or tabs are outside their group, A label-and-value list is built incorrectly and 8 more (all rules)
1.3.2 Meaningful Sequence W3C A Manual review
1.3.3 Sensory Characteristics W3C A Manual review
1.3.4 Orientation W3C AA Partly automated: The site works in only one screen orientation
1.3.5 Identify Input Purpose W3C AA Partly automated: Checkout fields are not filled in automatically
1.4.1 Use of Color W3C A Partly automated: Links in text look like normal text
1.4.2 Audio Control W3C A Partly automated: Some videos or sounds start playing with audio by themselves
1.4.3 Contrast (Minimum) W3C AA Partly automated: Text is hard to read because of low contrast
1.4.4 Resize Text W3C AA Partly automated: Visitors cannot zoom the page on mobile
1.4.5 Images of Text W3C AA Manual review
1.4.10 Reflow W3C AA Manual review
1.4.11 Non-text Contrast W3C AA Manual review
1.4.12 Text Spacing W3C AA Partly automated: Text spacing cannot be adjusted
1.4.13 Content on Hover or Focus W3C AA Manual review
2.1.1 Keyboard W3C A Partly automated: Keyboard users cannot reach some embedded content, Some scrollable areas cannot be used with a keyboard, A clickable image only works with a mouse
2.1.2 No Keyboard Trap W3C A Manual review
2.1.4 Character Key Shortcuts W3C A Manual review
2.2.1 Timing Adjustable W3C A Partly automated: The page reloads or redirects by itself
2.2.2 Pause, Stop, Hide W3C A Partly automated: The page uses outdated blinking-text markup, Some text scrolls and cannot be stopped
2.3.1 Three Flashes or Below Threshold W3C A Manual review
2.4.1 Bypass Blocks W3C A Partly automated: There is no quick way to skip to the main content
2.4.2 Page Titled W3C A Partly automated: The page has no title
2.4.3 Focus Order W3C A Manual review
2.4.4 Link Purpose (In Context) W3C A Partly automated: Clickable areas of an image have no description, Some links do not say where they go
2.4.5 Multiple Ways W3C AA Manual review
2.4.6 Headings and Labels W3C AA Manual review
2.4.7 Focus Visible W3C AA Manual review
2.4.11 Focus Not Obscured (Minimum) W3C (new in 2.2) AA Manual review
2.5.1 Pointer Gestures W3C A Manual review
2.5.2 Pointer Cancellation W3C A Manual review
2.5.3 Label in Name W3C A Partly automated: Buttons have a hidden name that differs from their visible text
2.5.4 Motion Actuation W3C A Manual review
2.5.7 Dragging Movements W3C (new in 2.2) AA Manual review
2.5.8 Target Size (Minimum) W3C (new in 2.2) AA Partly automated: Buttons and links are too small to tap easily
3.1.1 Language of Page W3C A Partly automated: The page does not say which language it is in, The page's language setting is wrong, The page declares two different languages
3.1.2 Language of Parts W3C AA Partly automated: Some text is marked with a wrong language code
3.2.1 On Focus W3C A Manual review
3.2.2 On Input W3C A Manual review
3.2.3 Consistent Navigation W3C AA Manual review
3.2.4 Consistent Identification W3C AA Manual review
3.2.6 Consistent Help W3C (new in 2.2) A Manual review
3.3.1 Error Identification W3C A Manual review
3.3.2 Labels or Instructions W3C A Partly automated: Some form fields have more than one label
3.3.3 Error Suggestion W3C AA Manual review
3.3.4 Error Prevention (Legal, Financial, Data) W3C AA Manual review
3.3.7 Redundant Entry W3C (new in 2.2) A Manual review
3.3.8 Accessible Authentication (Minimum) W3C (new in 2.2) AA Manual review
4.1.2 Name, Role, Value W3C A Partly automated: Clickable areas of an image have no description, Accessibility attributes are used on the wrong elements, Some elements have a braille label but no normal name, Custom buttons have no name and 23 more (all rules)
4.1.3 Status Messages W3C AA Manual review

How to test a site against WCAG

Start with an automated test — our WCAG checker checks one page for free — and then test by hand with a keyboard, zoom and a screen reader. How to combine both: how to test WCAG.

Quick ways in: all A and AA criteria on one screen in the WCAG 2.2 quick reference, recurring solutions in WCAG patterns, and how to describe images in the alt text guide.

Frequently asked questions

What does WCAG stand for?

Web Content Accessibility Guidelines. They are published by the World Wide Web Consortium (W3C) through its Web Accessibility Initiative (WAI).

What is the latest version of WCAG?

WCAG 2.2, published as a W3C Recommendation in October 2023. WCAG 3 is still a working draft and is not used by laws yet.

Is WCAG a law?

No. WCAG is a technical standard, but laws refer to it: in the EU through the harmonised standard EN 301 549, in the US through the ADA case law and Section 508.

Which WCAG level is required?

Level AA in almost every law and policy. Level A is the minimum, AAA is not required as a whole for any website.

How many success criteria does WCAG 2.2 have?

86: 31 at level A, 24 at level AA and 31 at level AAA, grouped in 13 guidelines under 4 principles. Level AA, the level laws refer to, means the 55 A and AA criteria. 4.1.1 Parsing is kept in the numbering as obsolete and removed.

Is WCAG an ISO standard?

Yes. WCAG is also published as ISO/IEC 40500. According to the W3C, ISO/IEC 40500:2025 is exactly the same as the October 2023 version of WCAG 2.2, and the W3C expects the December 2024 version to become ISO/IEC 40500:2026 by late 2026.

When was WCAG 2.2 published?

WCAG 2.2 became a W3C Recommendation on 5 October 2023. An updated version was published on 12 December 2024. It added 9 success criteria to WCAG 2.1 and removed 4.1.1 Parsing.

Is there a deadline for WCAG 2.2?

Not a universal one. WCAG itself has no deadline; the W3C encourages using the latest version. Deadlines come from laws and the standards they cite. In the EU, EN 301 549 V4.1.1, based on WCAG 2.2 AA, was published on 2 September 2026; until it is cited in the Official Journal, the cited version remains V3.2.1, based on WCAG 2.1.

Sources

  • W3C WAI, WCAG 2 Overview (versions and ISO/IEC 40500): https://www.w3.org/WAI/standards-guidelines/wcag/
  • W3C, Web Content Accessibility Guidelines (WCAG) 2.2: https://www.w3.org/TR/WCAG22/
  • W3C, What's new in WCAG 2.2: https://www.w3.org/WAI/standards-guidelines/wcag/new-in-22/
  • National Disability Authority (Ireland), EN 301 549 V4.1.1 published: https://nda.ie/news/en301549-published