Compliance

WCAG Conformance Levels: A vs AA vs AAA

Most organizations should target WCAG Level AA. It covers 50 success criteria that address the vast majority of real-world accessibility barriers, and it is the level referenced by the ADA, the European Accessibility Act, and Section 508. Level A is the bare minimum, and Level AAA is an aspirational target that is rarely required or achievable site-wide.

Level A — Minimum Accessibility

Level A contains 30 success criteria that represent the absolute baseline. A site failing Level A has fundamental barriers that prevent entire categories of users from accessing content at all.

Key Level A requirements:

• Text alternatives — Every non-text element (images, icons, charts) needs an alt text equivalent.
• Keyboard access — All functionality must be operable via keyboard alone, with no keyboard traps.
• No seizure triggers — Content must not flash more than 3 times per second.
• Page language — The document must declare its human language.
• Form error identification — Errors must be identified and described in text.

Level AA — The Standard Target

Level AA adds 20 criteria on top of Level A for a total of 50. This is the level that laws reference, auditors evaluate against, and plaintiff attorneys use as their benchmark. It addresses the accessibility needs of the broadest range of users with disabilities.

Key Level AA requirements:

• Color contrast 4.5:1 — Normal text must have a contrast ratio of at least 4.5:1 against its background. Large text requires 3:1.
• Resize text to 200% — Content must remain functional when text size is doubled.
• Consistent navigation — Navigation mechanisms must appear in the same order across pages.
• Reflow at 320px — Content must reflow without horizontal scrolling at 320 CSS pixels wide.
• Focus visible — Keyboard focus indicators must be visible.
• Target size 24×24px (WCAG 2.2) — Interactive targets must be at least 24×24 CSS pixels.

Level AAA — Highest Standard

Level AAA adds another 28 criteria for a total of 78. The W3C itself states that it is “not recommended that Level AAA conformance be required as a general policy for entire sites because it is not possible to satisfy all Level AAA success criteria for some content.” That said, individual AAA criteria can be valuable to adopt where practical.

Key Level AAA requirements:

• Enhanced contrast 7:1 — Normal text requires a 7:1 contrast ratio; large text requires 4.5:1.
• Sign language — Pre-recorded video must provide sign language interpretation.
• Extended audio description — Video must include extended audio descriptions where pauses are insufficient.
• Reading level — Content must be understandable at a lower secondary education reading level, or a simplified version must be provided.
• No timing — Time limits are not allowed at all (with narrow exceptions).

Side-by-Side Comparison

Which Level Do You Need?

The answer depends on your jurisdiction and sector, but for the vast majority of organizations the answer is Level AA:

• ADA (United States) — Title II requires WCAG 2.1 AA. Title III courts reference WCAG AA in settlements. Full ADA guide →
• EAA (European Union) — EN 301 549 maps to WCAG 2.1 AA. Full EAA guide →
• Section 508 (US federal) — Requires WCAG 2.0 AA for federal agencies and contractors.
• AODA (Ontario, Canada) — Requires WCAG 2.0 AA for organizations with 50+ employees.

If no law applies to you yet, target AA anyway. It is the industry-standard baseline, the level most accessibility overlays and tools measure against, and the level that will be referenced by future regulations.

Start checking your site against WCAG Level AA. Try SweepHound's free scan for an automated WCAG scan with prioritized remediation guidance and recommended manual follow-up.