WCAG

WCAG is a set of testable success criteria, not a vague aim. Each criterion is a specific requirement, such as giving images text alternatives or making every function usable with a keyboard, and each sits at a conformance level: A, the minimum; AA, the level most laws and policies reference; and AAA, the strictest. Accessibility is the broader goal, and WCAG is the yardstick most organisations use to measure it.

WCAG 2.2, published by the W3C in October 2023, builds on versions 2.0 and 2.1 rather than replacing them, and the W3C states that content meeting 2.2 also meets 2.0 and 2.1; the one criterion 2.2 dropped, on code parsing, may still need checking where a contract names an older version. A successor, WCAG 3, is being developed with a different structure, but the 2.x versions remain the reference in law and practice.

How it works

WCAG is organised under four principles, often shortened to POUR: content must be perceivable, operable and understandable, and it must work reliably with browsers and assistive technologies such as screen readers. Under them sit guidelines and then success criteria. Familiar criteria at levels A and AA include a colour contrast ratio of at least 4.5:1 for normal text and 3:1 for large text, visible keyboard focus, text alternatives for images through alt text, captions for pre-recorded video, labelled form fields and pages that still work when text is enlarged to 200 percent.

Conformance is checked with a mix of automated tools and manual testing. Automated scanners catch problems such as missing alt text and low contrast, but many criteria, such as whether alt text is meaningful or a page works by keyboard alone, need a person to test.

Many organisations publish an accessibility statement saying which version and level they target, where they fall short and how visitors can report problems, and public-sector bodies in the EU are required to publish one. For a business, writing a statement is a useful exercise in itself, because it forces an honest list of known gaps and a plan to close them.

Example

An online shop audits its checkout against WCAG 2.2 AA. Automated tools flag low-contrast grey labels and images without alt text. Manual testing finds more: the delivery date picker cannot be used with a keyboard, errors appear only as red borders, and the focused field disappears behind a sticky header when tabbing through the form. Each failure is mapped to its success criterion, fixed and retested.

The fixes are mostly modest. The date picker is replaced with one that works with the keyboard, with a plain text field as a fallback. Error messages are written as text beside each field and announced to screen readers. The sticky header is given room so that the focused field scrolls into view. The shop then adds an accessibility check to its release routine, so new products, banners and campaign pages are checked before they go live.

Why it matters for your business

WCAG AA is the benchmark most accessibility laws and procurement rules point to. In the EU, public-sector websites must meet requirements based on it, and the European Accessibility Act has applied since June 2025 to many consumer services, including online shops and banking, with an exemption for the smallest service businesses. Beyond compliance, accessible sites work better for older customers, people on phones in bright light and anyone in a hurry. Aim for AA; full AAA is rarely required.

Common mistakes

• Relying on an automated scan or an accessibility overlay widget and assuming the site conforms.
• Testing only with a mouse and never using the site by keyboard alone.
• Fixing accessibility once before launch and letting new content break it afterwards.
• Rebuilding buttons, links and form fields from generic elements instead of using semantic HTML, which keyboards and screen readers already understand.

Questions people ask

What is the difference between WCAG A, AA and AAA?

They are conformance levels. Level A covers the most basic requirements, without which some people cannot use a site at all. Level AA adds criteria such as 4.5:1 text contrast and visible keyboard focus, and is the level most laws and contracts reference. Level AAA is the strictest and is not expected for entire sites.

Is WCAG a legal requirement?

WCAG itself is a technical standard, not a law, but many laws and regulations point to it. In the EU, public-sector websites must meet accessibility requirements based on WCAG, and the European Accessibility Act extends similar duties to many consumer services. Other countries have their own rules, so check what applies to your sector and market.

How do I check if my website meets WCAG?

Start with a free automated checker to catch obvious issues such as missing alt text and low contrast, then test manually: use the site by keyboard alone, zoom text to 200 percent, try a screen reader and check forms and error messages. For a formal conformance claim, commission an audit from an accessibility specialist.