WCAG Contrast Checker
Check if two colors meet WCAG AA and AAA contrast requirements.
Quick answer: Check if two colors meet WCAG AA and AAA contrast requirements.
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Frequently asked questions
- Is the contrast checker free?
- Yes — free, with no signup or limits.
- Which formula do you use?
- The official WCAG 2.1 relative-luminance formula — the same one Google's Lighthouse uses.
- What ratios pass?
- AA needs 4.5:1 for normal text or 3:1 for large text; AAA raises that to 7:1 and 4.5:1.
- Can I check transparent colors?
- WCAG doesn't define ratios for transparent foregrounds — pre-blend your color against a solid background first.
- Is data uploaded?
- No — the check runs in your browser.