WCAG levels explained: A, AA and AAA
Updated October 14, 2026 · 7 min read
WCAG sorts its success criteria into three levels: A, AA and AAA. When a law, a contract or a tender says a website must meet "WCAG AA", it means every level A and every level AA criterion of a given WCAG version. This page explains what each level covers, how conformance is counted, why almost every law settles on AA and what you get, and lose, by aiming for AAA.
This is general information, not legal advice. For the background of the guidelines themselves, start at what WCAG is.
The three levels in short
| Level | What it means | WCAG 2.2 criteria | Typical use |
|---|---|---|---|
| A | The minimum: without it some people cannot use the page at all | 31 | Never the target on its own |
| AA | A and AA together: removes the most common barriers | 31 + 24 = 55 | Laws, policies, contracts |
| AAA | A, AA and AAA together: the strictest level | 55 + 31 = 86 | Selected criteria for some content |
Levels are cumulative. "Level AA" never means only the AA criteria; it always includes level A. "Level AAA" includes all three.
Level A
Level A criteria remove barriers that block people completely. Images need a text alternative (1.1.1), everything must work with a keyboard (2.1.1) without a keyboard trap (2.1.2), the page needs a language (3.1.1) and every control needs a name, role and value (4.1.2).
Level AA
Level AA adds what most people with disabilities need in everyday use: text contrast of 4.5:1 (1.4.3), contrast of 3:1 for icons and field borders (1.4.11), text that can be enlarged to 200% (1.4.4), layouts that reflow on a narrow screen (1.4.10), a visible focus (2.4.7) and, since WCAG 2.2, targets of at least 24 by 24 CSS pixels (2.5.8).
Level AAA
Level AAA goes further, often in ways that suit some sites but not others: sign language interpretation, extended audio description, a reading level no harder than lower secondary education, no timing at all.
How WCAG conformance works
Conformance is not a percentage. The WCAG 2.2 conformance requirements set five conditions, and all of them apply:
- Conformance level. The page satisfies every success criterion of the chosen level and of the levels below it, or a conforming alternate version is provided.
- Full pages. Conformance is for whole pages. You cannot leave out the chat widget, the cookie banner or the embedded map and still claim it.
- Complete processes. If a page is one step of a process — product, cart, checkout, payment — every page of that process has to conform. One inaccessible payment step breaks the whole checkout.
- Only accessibility-supported ways of using technologies. The techniques you rely on must actually work with assistive technologies people use.
- Non-interference. Technologies that are not accessibility supported must not block the rest of the page, for example by trapping the keyboard or playing sound.
So "we meet 90% of AA" is not a WCAG statement. A page either meets a level or it does not, and the accessibility information you publish should list the parts that do not meet it yet. Our accessibility statement guide explains how.
Why laws ask for WCAG AA
Lawmakers wanted a level that removes the barriers most people meet and that any kind of website can reach. That is AA:
- European Union: the European Accessibility Act relies on the harmonised standard EN 301 549. Its web chapter takes over the WCAG success criteria at levels A and AA — WCAG 2.1 in V3.2.1, WCAG 2.2 in V4.1.1. Read EN 301 549 V4.1.1 and WCAG 2.2 and the EAA guide.
- United States: Section 508 refers to WCAG 2.0 AA; the ADA Title II rule for state and local governments to WCAG 2.1 AA; for private businesses under Title III, WCAG 2.1 or 2.2 AA is the practical yardstick. See ADA website compliance.
- Contracts and tenders usually copy one of these, often as "WCAG 2.1 AA" or "WCAG 2.2 AA".
When a requirement says "WCAG 2.1 AA", the version matters: WCAG 2.2 AA contains every 2.1 AA criterion except the removed 4.1.1 Parsing and adds six more. A site that meets 2.2 AA therefore also meets 2.1 AA. What changed: WCAG 2.1 vs 2.2.
WCAG AA vs AAA: the criteria people look up
These AAA criteria come up most often, usually because a design tool or checker shows an "AAA" result next to the AA one:
| AAA criterion | What it asks | AA counterpart |
|---|---|---|
| 1.4.6 Contrast (Enhanced) | Text 7:1, large text 4.5:1 | 1.4.3: 4.5:1 and 3:1 |
| 2.5.5 Target Size (Enhanced) | Targets at least 44 by 44 CSS pixels | 2.5.8: 24 by 24 CSS pixels |
| 2.4.12 Focus Not Obscured (Enhanced) | No part of the focused element is hidden | 2.4.11: not entirely hidden |
| 2.4.13 Focus Appearance | A focus indicator of a minimum size and contrast | 2.4.7: focus is visible |
| 3.3.9 Accessible Authentication (Enhanced) | No cognitive test at login, not even object recognition | 3.3.8: with some exceptions |
| 1.2.6 Sign Language (Prerecorded) | Sign language for prerecorded audio in video | none |
| 1.4.8 Visual Presentation | Line length, spacing and colour choices for blocks of text | 1.4.12: text spacing can be changed |
| 2.2.3 No Timing | No time limits at all, with few exceptions | 2.2.1: time limits can be adjusted |
| 3.1.5 Reading Level | Simpler version for text above lower secondary level | none |
You can check 1.4.6 for any colour pair with our contrast checker, which shows the AA and AAA results side by side.
Why the W3C does not recommend AAA as a general policy
The WCAG text says it directly: it is not recommended that Level AAA conformance be required as a general policy for entire sites, because some content cannot satisfy all AAA criteria. A live video stream cannot have prerecorded sign language; a legal text or a product safety note may not be rewritable to a lower secondary reading level; a brand colour may not reach 7:1 on every background.
That does not make AAA useless. A practical approach:
- Meet level AA on every page and in every process. That is what laws and customers expect.
- Adopt the AAA criteria that are cheap for you, for example 44-pixel targets on mobile, 7:1 contrast for body text, a strong focus indicator.
- Do not claim AAA for the site unless every AAA criterion is met on every page.
How to check which level you reach
An automated test can find many A and AA failures quickly — missing alternative text, low contrast, buttons without names, missing page language. It cannot confirm that a page meets a level, because a large part of the criteria need human judgement. Start with our free WCAG checker, then follow how to test WCAG for the keyboard, zoom and screen reader steps. Our automated check is an automated check, not a full audit, and not legal advice.
Frequently asked questions
What are the three WCAG levels?
A, AA and AAA. Every success criterion has one level. Level A is the minimum, AA adds the criteria most users need, AAA is the strictest. Each level includes the levels below it.
What does WCAG AA mean?
A page meets WCAG level AA when it satisfies every level A and every level AA success criterion of the WCAG version you refer to, for example the 55 A and AA criteria of WCAG 2.2.
What is the difference between WCAG AA and AAA?
AAA adds stricter criteria, for example contrast of 7:1 instead of 4.5:1 (1.4.6), targets of 44 by 44 CSS pixels (2.5.5) and sign language for prerecorded video (1.2.6). Many of them cannot be met by every kind of content.
Is WCAG AAA required by law?
Not as a whole. EN 301 549 in the EU, Section 508 and the ADA Title II rule in the US refer to level AA. The W3C itself does not recommend requiring AAA as a general policy for entire sites.
Is WCAG 2.1 AA still enough?
Many laws still name WCAG 2.1 AA, for example the harmonised EN 301 549 V3.2.1 and the ADA Title II rule. WCAG 2.2 AA includes all of 2.1 AA except the removed 4.1.1 Parsing, so aiming for 2.2 AA covers both.
Sources
- W3C, WCAG 2.2, conformance requirements: https://www.w3.org/TR/WCAG22/#conformance-reqs
- W3C, What's new in WCAG 2.2: https://www.w3.org/WAI/standards-guidelines/wcag/new-in-22/
- W3C, Understanding 2.5.5 Target Size (Enhanced): https://www.w3.org/WAI/WCAG22/Understanding/target-size-enhanced.html