accessibility
WCAG levels (A, AA, AAA)
What do the WCAG conformance levels A, AA and AAA mean?
WCAG - the Web Content Accessibility Guidelines - groups its success criteria into three conformance levels: A (the bare minimum), AA (the standard most organisations and laws target), and AAA (the highest, often impractical to meet site-wide). Each level builds on the last, so AA includes all of A, and AAA includes all of AA.
Also known as: wcag levels, wcag a aa aaa, conformance levels, wcag conformance
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Watch the recap 0:53
The demo
WCAG's three levels, made concrete. Pick a level to see what it demands - and watch a sample paragraph get more legible as the contrast bar rises from none, to AA, to AAA.
The quick brown fox jumps over the lazy dog. This sample text is rendered at the text contrast this level requires.
What this demo shows (text version)
A selector switches between WCAG's three conformance levels. For each, the demo lists what it requires and renders a sample paragraph at that level's text-contrast ratio. Level A has no general contrast requirement, so the sample is a faint grey that's hard to read. Level AA requires 4.5:1, so the sample becomes comfortably legible. Level AAA pushes to 7:1, darker still.
The levels build on each other (AA includes A; AAA includes AA). A is the bare minimum (alt text, no colour-only meaning, no keyboard traps); AA is the real-world and legal target most should meet (contrast, visible focus, reflow, labels); AAA is the highest and rarely achievable site-wide. In practice, "accessible" means WCAG AA - a floor to clear, not a ceiling.
A is the floor (fix the showstoppers), AA is the real-world target almost everyone should hit and the legal bar in much of the world, and AAA is aspirational - apply it where you can, especially for critical content, but it's rarely realistic everywhere. "Accessible" in practice means WCAG 2.x AA. Treat the levels as a floor to clear, not a ceiling to admire.
Step up the levels and the same paragraph went from barely-legible grey to comfortably readable, because AA demands 4.5:1 contrast and AAA pushes to 7:1 where A asks for none. The levels aren't abstract grades - each is a concrete set of "must" rules, and AA is the one the world actually expects you to meet.
Level A is the minimum: it removes the most fundamental barriers - images need text alternatives, content doesn't rely on colour alone, nothing is a keyboard trap - but notably has no general text-contrast requirement, so an A-only page can still be hard to read. It's the floor, not a finish line.
Level AA is the practical target. It's what "accessible" means in most procurement, policy and law, and it adds the criteria that matter day to day: 4.5:1 contrast for normal text, a visible focus indicator, reflow and resize to 200% without loss, labels and instructions, consistent navigation. If you aim at one level, aim here.
Level AAA is the highest bar - 7:1 contrast, no time limits, sign-language interpretation for audio, and more. WCAG itself says it's not recommended as a blanket requirement for entire sites, because some content can't meet it. Reach for AAA selectively, especially for critical or widely-used flows, rather than treating failure to hit it everywhere as failure.