The Web Content Accessibility Guidelines are the technical standard that almost every national accessibility law points to. Know these and you understand what the law actually requires.
The Web Content Accessibility Guidelines (WCAG) are published by the World Wide Web Consortium (W3C) through the Web Accessibility Initiative. Version 2.2 became a W3C Recommendation on 5 October 2023, superseding WCAG 2.1 (2018) and WCAG 2.0 (2008). All three versions are backward-compatible: everything that conformed to 2.0 still conforms to 2.2 if you add the newer criteria.
WCAG 2.2 defines 87 success criteria — testable statements like “all non-text content has a text alternative” or “colour is not the only way to convey information.” Each criterion is assigned a conformance level (A, AA or AAA) based on how fundamental it is to access for people with disabilities.
WCAG is content-type agnostic: the same criteria apply to websites, web apps, PDFs (through PDF/UA), native mobile apps and software interfaces (through EN 301 549 and Section 508). Adoption is near-universal — from the ADA in the United States to the EAA in Europe, the DDA in Australia, the ACA in Canada and the Equality Act in the UK.
Every one of the 87 success criteria sits under one of four principles. If your content fails any principle, people with disabilities cannot use it.
Information and UI components must be presentable in ways users can perceive — it can’t be invisible to every one of their senses.
UI components and navigation must be operable — users must be able to use the interface with whatever input device they have.
Information and operation must be understandable — content and behaviour can’t be beyond users’ comprehension.
Content must be robust enough to be interpreted reliably by a wide variety of user agents, including assistive technologies.
AA is the level almost every law points to. A is the floor below which content is unusable for many people. AAA is the aspirational ceiling.
30 criteria · minimum
The lowest level. If you fail Level A, some people with disabilities cannot access your content at all. Covers basics like text alternatives, keyboard access, no seizure triggers and language of page. Required by every single accessibility law.
28 additional criteria · legal target
The conformance target of virtually every national law: ADA, EAA, EN 301 549, Section 508, DDA, ACA, AODA, Equality Act. Adds contrast ratios, resizable text, captions, consistent navigation and input error prevention. This is the level you should audit to.
29 additional criteria · aspirational
The highest level. W3C specifically notes that full AAA conformance is not required for all content and may be impossible for some content types. Useful for critical services (healthcare, finance, government) but not mandated by law.
WCAG 2.2 added criteria for touch targets, drag-only interactions, visible focus, redundant entry and cognitive load. Parse (4.1.1) was obsoleted — browsers now handle it reliably.
When a component gets keyboard focus it must not be entirely hidden by author-created content like sticky headers or cookie banners.
AAStricter version: no part of the focused component may be hidden by author-created overlays.
AAAFocus indicators must have enough contrast against both the focused element and the background, with a minimum outline area.
AAAAll drag-and-drop functionality must have a single-pointer alternative (click or tap). Critical for users with motor impairments.
AAClickable targets must be at least 24×24 CSS pixels, with exceptions for inline, user-agent and essential targets.
If help mechanisms (contact info, FAQ, chat) appear on multiple pages, they must appear in the same relative order.
AInformation previously entered in the same session must be auto-populated or available — don’t make users retype their address.
ANo cognitive function test (puzzles, memorising strings) required to log in, unless there’s an alternative or object recognition/personal content.
AAStricter version: no cognitive function test even with object-recognition alternatives. Password managers and biometrics are the path forward.
AAAJurisdictions update at different speeds. 2.2 is now the target in the UK and Australia; the US and EU still reference 2.1; Section 508 still references 2.0. All are backward-compatible.
Our Web Accessibility Checker tests against 77 WCAG 2.2 A and AA criteria in real time and gives you the specific fix for each failure.