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 minimum), AA (the most common organisational target, referenced by many accessibility regimes), and AAA (the highest, often unfeasible to meet site-wide). Each level builds on the previous one, 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 most common organisational conformance target and is incorporated or referenced by many accessibility regimes - though obligations vary by country, sector, standard and WCAG version, so check the applicable law; AAA is aspirational, worth applying to critical content but rarely realistic everywhere. 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.
The difference between WCAG AA and AAA is that AAA adds stricter success criteria - but you can’t meet it site-wide without major effort. Try the demo to see how AA and AAA criteria stack. While AA is the most common target, AAA is often unfeasible - so focus on AA first, then apply AAA where it matters most, like in critical user journeys. See how it works in our demo.