WCAG 2.1 Explained: What Every Website Owner Needs to Know

WCAG 2.1 (Web Content Accessibility Guidelines) is the internationally recognised standard for making websites usable by everyone, including people who rely on screen readers, keyboard navigation, captions, or high contrast. It is the benchmark courts and regulators point to when they assess whether a website is accessible.

The three conformance levels

• Level A — the absolute minimum. Failing Level A means some users are completely blocked (for example, an image with no alt text, or a form field with no label).
• Level AA — the level most laws and policies target, including ADA-related expectations. It covers things like colour contrast, resizable text, and consistent navigation.
• Level AAA — the gold standard. Important for some audiences, but not expected across an entire site.

Target Level AA. It's the practical, widely-referenced bar for compliance.

The four principles (POUR)

WCAG is organised around four ideas: content must be Perceivable, Operable, Understandable, and Robust. Every success criterion maps back to one of these.

How VitalSite helps

VitalSite runs axe-core — the same open-source engine used by Chrome DevTools and Lighthouse — against every page of your domain, then maps each issue to its exact WCAG 2.1 criterion with a plain-English fix. Run a free scan to see your accessibility score and your top issues.