What is WCAG, and what does WCAG 2.2 AA require?

What WCAG is

WCAG is published by the W3C's Web Accessibility Initiative. It is organised around four principles: content must be perceivable, operable, understandable and robust. Under them sit testable success criteria, such as text alternatives for images, sufficient colour contrast, full keyboard access and visible focus.

The versions

• WCAG 2.0, from 2008, is still referenced by some older laws.
• WCAG 2.1, from 2018, added criteria for mobile, low vision and cognitive needs. Many current laws point to 2.1 AA.
• WCAG 2.2, from October 2023, is the current recommendation. It adds criteria such as larger target sizes, visible focus that is not hidden, and accessible authentication without memory puzzles.
• WCAG 3 is in development and is not yet a standard. Each version is backwards compatible: meeting 2.2 AA also meets 2.1 AA and 2.0 AA.

The levels

• A: the minimum. Without it, some people cannot use the content at all.
• AA: the practical target for most organizations and laws.
• AAA: the highest level, not expected for entire sites because some criteria cannot be met for all content.

What AA means in practice

• Images, icons and controls have text alternatives.
• Text has a contrast ratio of at least 4.5 to 1, or 3 to 1 for large text.
• Everything works with a keyboard, with a visible focus indicator.
• Forms have labels, and errors are explained in text.
• Pages have a language, titles, headings in a logical order and a way to skip repeated navigation.
• Content works when zoomed to 200 percent and at narrow widths without horizontal scrolling.
• Video has captions, and nothing flashes more than three times a second.

Which laws refer to it

The European Accessibility Act, applying since June 2025, relies on the EN 301 549 standard, which incorporates WCAG 2.1 AA. In the United States, the Department of Justice's rule for state and local governments adopts WCAG 2.1 AA, and courts often refer to WCAG in cases against businesses. Exact obligations depend on the country, sector and size of the organization, so check which apply to you.

How to test against it

• Run automated checks for the issues machines can detect.
• Navigate every key journey with only the keyboard.
• Zoom to 200 percent and test at a narrow width.
• Use a screen reader, such as VoiceOver or NVDA, on your main pages.
• Check colour contrast for text and controls.

Automated tools find only part of WCAG failures. Conformance can only be established with manual testing.

What a scan can and cannot tell you

WebAuditOS runs source-based accessibility checks on eligible crawled HTML and browser checks on sampled pages, including missing alt text, page language, heading order, skip links, zoom being disabled and tap target size, and reports them with evidence.

It cannot establish WCAG conformance. It does not test keyboard journeys, screen reader behavior, the meaning of alternatives or content behind a login. Use its findings to prioritize, then test manually.

A clean automated result is a good start, not a conformance claim.

Short answers

What WCAG level should I aim for? AA, in the current version, 2.2.

Is WCAG a law? No. It is a standard that many laws refer to.

Can a tool make my site WCAG compliant? No. Tools find some issues. Conformance needs manual testing.

What is the most common WCAG failure? Low colour contrast, followed by missing alt text and form labels.