ValidateThis

WCAG contrast checker

Related tools

Validators and utilities that complement WCAG contrast checker — same session, no sign-up.

Compute WCAG 2.x contrast ratio from two #RGB or #RRGGBB colors using sRGB relative luminance. Heuristic AA/AAA hints in UI.

#RGB or #RRGGBB only — WCAG 2.x contrast ratio for sRGB hex pairs.

How to use this tool

  1. Paste your sample in the input (or fetch from URL if this tool supports it).
  2. Run the main action on the page to execute WCAG contrast checker.
  3. Read the result, fix the source data or config, and re-run if needed.

What this check helps you catch

  • Compute WCAG 2.x contrast ratio from two #RGB or #RRGGBB colors using sRGB relative luminance. Heuristic AA/AAA hints in UI.
  • Limits called out in the description (what this tool does not verify — e.g. live network reachability, issuer databases, or strict schema contracts unless stated).
  • Structural or syntax mistakes that would break parsers, serializers, or the next step in your workflow.

FAQ

What does WCAG contrast checker do?
Compute WCAG 2.x contrast ratio from two #RGB or #RRGGBB colors using sRGB relative luminance. Heuristic AA/AAA hints in UI. Use the form above, then see “How to use” and “What this check helps you catch” for behavior detail.
Is this a substitute for server-side validation?
No. Use it for manual checks and triage; production systems should still validate and authorize on the server.
Where does processing happen?
Most validators here run in your browser. If a tool calls an API, that is stated on the page. See the site privacy policy for data handling.