Published October 3, 2026

W3C evaluation tools, WCAG 2.2

Does a passing accessibility scan mean a site meets WCAG?

No. A scanner reports some failures and misses others. WCAG conformance means the success criteria are true of the page, or of a complete process such as search or checkout. A score of 100 is not that test. The W3C says evaluation tools help find problems and that no tool can determine accessibility on its own. The explanation is on Selecting Web Accessibility Evaluation Tools.

What can a scanner check reliably?

Tools are useful on the failures that are present or absent in the code:

• An image with no alt attribute at all.
• A form control with no label and no other accessible name.
• Text whose computed color contrast falls below the ratios in WCAG 2.1 Level AA. See color contrast.
• A page with no language set on the html element.
• Some missing document titles and some empty links and buttons.

What does a scanner miss?

These criteria need a person, because the tool cannot tell whether the content is right:

• Whether alt text matches the image. A present attribute can still fail if the words are wrong or if a decorative image is announced. See alt text.
• Whether a heading or label describes the section. A tool can see that an h2 exists.
• Whether a person can reach every control, see focus, and leave a dialog without a mouse.
• Whether an error message names the field and how to correct it. See accessible forms.
• Whether captions match the speech, and whether a PDF is the only copy of the information. See video and PDFs.
• Reading order when CSS moves content visually away from the order in the HTML.

Why is there no official scanner percentage?

WCAG 2.2 defines conformance for a web page or a complete process. It does not say that covering a fraction of the criteria with a tool is enough. Level AA includes every Level A criterion. The conformance rules are in the W3C Recommendation. A product that reports “95 percent” is using its own formula. That number is not a WCAG claim.

Does a scanner score satisfy the Title II web rule?

No. The Department of Justice rule for state and local government websites names WCAG 2.1 Level AA. It does not name a vendor score. Governments of 50,000 or more have until April 26, 2027. Smaller governments and special districts have until April 26, 2028. The scope is on the Title II web rule page. Private businesses are covered by Title III. ADA.gov’s web guidance is about access to the content, not about a scan result. An overlay that advertises a higher score has the same limit. That case is on the overlay page.

How should a scan be used?

Run the tool on the templates, not on a single marketing page. Treat each finding as a candidate: name the page, the success criterion, and whether a person confirmed it. Then tab through the same templates and listen to them in a screen reader. Fix the template so every page built from it changes at once. Recheck after the code ships. That sequence is an audit, then remediation, then a recheck when the site changes. The scan is the first pass. It is not the record of conformance.