Guide
WCAG compliance check: what to test and how
WCAG, the Web Content Accessibility Guidelines, is the standard every accessibility law points at: US courts and the DOJ reference it for the ADA, and the EU's EN 301 549 builds on it for the European Accessibility Act. "Checking WCAG compliance" therefore means something specific: evaluating your pages against the testable success criteria of WCAG 2.1 level AA. Here is what that involves and how to do it at three depths.
Version and level, decided quickly
- WCAG 2.1 level AA is the benchmark. Level A alone is not considered adequate anywhere that matters; AAA is aspirational and not expected of whole sites. When a contract, law, or letter says "WCAG compliant" without qualification, 2.1 AA is what it means.
- WCAG 2.2 added nine criteria in 2023 (focus appearance, dragging alternatives, consistent help, and others). Adopt it for new builds; know that the legal references still say 2.1 AA, which is also what our audits test.
What a real check covers
WCAG 2.1 AA has 50 success criteria across four principles: perceivable, operable, understandable, robust. About a third are machine-decidable with certainty: an image either has an alt attribute or it does not, a contrast ratio either clears 4.5:1 or fails. The rest need judgment: whether the alt text says anything useful, whether keyboard focus moves in an order that makes sense, whether the checkout can actually be completed with a screen reader. Any "compliance checker" that returns a percentage score without a human or judgment layer is scoring the first third and silently skipping the rest; our methodology page shows how we split the two layers explicitly.
Three ways to run the check
| Depth | Cost, time | Right when |
|---|---|---|
| Free instant check | $0, one minute | You want the machine-checkable layer on one page, now. |
| Automated audit | $149, 24 hours | You want every page mapped with evidence and fix instructions, and you are the only reader. |
| Signed audit | $490, 48-72 hours | The result has to convince someone else: a court, a regulator, procurement, your customer's compliance team. |
Common questions
Can a website be 100% WCAG compliant?
Conformance is defined per page and it is fragile: one uploaded image without alt text technically breaks it. Serious organizations treat 2.1 AA as a state to reach and maintain, publish an accessibility statement that names known gaps, and re-check after changes rather than framing a certificate on the wall. Anyone selling you a permanent compliance badge is selling exactly what the standard does not offer.
Is WCAG itself the law?
No; WCAG is a W3C standard that laws reference. In the US the ADA is the law and courts use WCAG as the measure; in the EU the EAA is the law and EN 301 549 carries WCAG into it. Which law applies to you depends on where you sell: see is my website ADA compliant for the US and the European Accessibility Act guide for the EU; the technical target is the same either way.
What about Section 508?
Section 508 applies to US federal agencies and their vendors, and its refresh incorporated WCAG 2.0 AA. If you sell to the US government the paperwork is a VPAT/ACR, which is an audit-shaped document; the underlying testing is the same work.