WCAG levels: A, AA and AAA

At a glance

Why it matters

The level you claim is the level you are held to. Conformance means no content violates the success criteria at that level, across full pages and complete processes, so a checkout with one Level A failure on step three does not conform at Level A (W3C, Understanding Conformance). The versions stack rather than replace each other: WCAG 2.1 added 17 success criteria in 2018, and WCAG 2.2, published 5 October 2023, added 9 more and retired 4.1.1 Parsing (WCAG 2 Overview). "AA" with no version number is therefore an incomplete claim.

Which WCAG level should you aim for?

• 1. Start from the law or contract that applies. The ADA Title II web rule names WCAG 2.1 AA; procurement questionnaires and VPATs ask for a level and a version. That is your floor.
• 2. Claim AA at the newest version you can. WCAG 2.2 AA is 2.1 AA plus the new criteria, among them a focused control that stays on screen, 24 by 24 CSS pixel targets and no cognitive tests at login (What's New in WCAG 2.2).
• 3. Treat A as a floor, not a goal. Level A alone does not require a visible focus indicator (2.4.7) or 4.5:1 text contrast (1.4.3); both are Level AA.
• 4. Adopt AAA criteria, not the AAA level. Pick the ones that fit your product, such as 7:1 enhanced contrast or focus appearance, and write them into your design system; claiming the level for a whole site is what the W3C advises against.
• 5. Write the claim properly. The W3C's required components are the date, the guidelines version and URI, the level, and the scope of pages covered (conformance claims).

Examples

Common mistakes

• Claiming "WCAG compliant" with no level or version. A claim names a version, a level and a scope; without them nobody can check it.
• Aiming at AAA for the whole site. The W3C says some content cannot meet every AAA criterion; adopt the AAA criteria that fit instead.
• Reading levels as severity. A Level A failure is not automatically worse than a Level AA one; the levels group criteria by how broadly they can be applied, not by harm.
• Claiming AA from an automated scan alone. A scanner decides a subset of the A and AA criteria; keyboard and screen reader tests cover the rest.
• Forgetting complete processes. Conformance covers every page in a flow. A checkout conforms only if every step does.

Frequently asked questions

What is the difference between WCAG Level A, AA and AAA?

They are nested conformance levels. Level A means every Level A success criterion is met. Level AA means every A and AA criterion is met. Level AAA means every A, AA and AAA criterion is met. The W3C assigned each criterion a level after weighing how essential it is, how broadly it can be applied and how much design change it needs, and it says the levels are not a ranking of importance.

Is WCAG 2.2 AA the same as WCAG 2.1 AA?

No. WCAG 2.2 keeps every 2.1 criterion except 4.1.1 Parsing, which is obsolete, and adds nine new criteria. Six of the nine sit at Level A or AA, so a page that met 2.1 AA has new work to do for 2.2 AA, including focus not obscured, target size and accessible authentication. WCAG 2.2 was published on 5 October 2023.

Can a website be fully WCAG AAA compliant?

Rarely for an entire site, and the W3C does not recommend requiring it as a general policy, because some content cannot satisfy every Level AAA criterion. Teams usually claim Level AA for the site and adopt individual AAA criteria where they fit, such as enhanced text contrast, a larger focus indicator or sign language for key videos.

Which WCAG level do laws require?

Level AA is the level regulations reference. In the United States, the ADA Title II web rule for state and local government names WCAG 2.1 Level AA; our guide covers its compliance deadlines. The European Accessibility Act applies to companies serving EU customers; our guide covers its WCAG requirements and the fines by country. Check the version each rule names, since it is not always the newest one.