Concepts

Conformance level

Also: WCAG level

WCAG's tiered grading: **A** (minimum), **AA** (broadly required), **AAA** (highest). Each criterion is assigned exactly one level. Most laws and contracts target Level AA.

WCAG defines three conformance levels — A, AA, and AAA — that signal the strictness of the accessibility requirements a site claims to meet. Each WCAG success criterion is assigned exactly one level. Conformance “to” a level requires passing every criterion at that level and all lower levels.

What each level covers

Level A — the absolute minimum. Failing A criteria typically makes content unusable for one or more disability populations. Examples: keyboard accessibility (2.1.1), text alternatives for non-text content (1.1.1), no flashing content above three flashes per second (2.3.1). A site that fails Level A is not accessible in any meaningful sense.

Level AA — the practical compliance target. Adds requirements that significantly improve usability but aren’t strictly “essential.” Examples: colour contrast 4.5:1 for normal text (1.4.3), captions for pre-recorded video (1.2.2), resize text up to 200 % without loss (1.4.4), focus visible (2.4.7). Nearly every accessibility law cites AA as the obligation: the ADA (de facto), the EAA (via EN 301 549), PSBAR, Section 508, AODA.

Level AAA — the highest grade. Often impractical site-wide because several criteria are situational or genuinely difficult. Examples: sign language interpretation for all pre-recorded video (1.2.6), contextual help on every form (3.3.5), live captions for audio (1.2.4). The W3C explicitly notes that “it is not recommended that Level AAA conformance be required as a general policy for entire sites.”

The crucial misunderstanding

A common claim — almost always wrong — is “we meet Level A, and we meet half the AA criteria, so we’re partially AA compliant.”

WCAG conformance is binary at each level. To claim “Level AA,” you must pass every Level A criterion and every Level AA criterion. Missing one Level A criterion makes the entire claim invalid; partial AA is not a thing the standard recognises.

The W3C says this explicitly: “It is not possible to conform at Level AA without also conforming at Level A.” If a site sells itself as “AA compliant” but fails any single Level A criterion, the claim is false under the standard’s own definitions.

Why this matters operationally

Two procurement-level consequences:

  1. VPATs that mark some AA criteria “Supports” and some “Does Not Support” are not claiming Level AA conformance. They are claiming partial conformance, with a specific list of gaps. That may still be acceptable to the buyer (and is more honest than blanket claims), but the buyer should not assume it is “AA.”

  2. Legal exposure tracks the actual conformance, not the marketing. A site that says “WCAG 2.1 AA compliant” while failing a Level A criterion has misrepresented its compliance. Courts and regulators have treated this as material — it’s not just a documentation issue.

Picking a target

For nearly every commercial site or service in 2026, the right target is WCAG 2.2 Level AA. AAA is appropriate for sites where the audience heavily overlaps disability communities (some government services, disability-focused publishers, accessible-design firms), and even there it’s typically targeted criterion by criterion rather than wholesale.