Text Contrast Checker
Check text and background contrast against WCAG AA and AAA requirements. Shows the exact ratio, pass/fail for normal and large text, and a side-by-side swatch preview.
How to use
- Pick the text color.
- Pick the background color.
- Read the ratio and pass/fail badges.
Frequently asked questions
What contrast ratio is required for WCAG AA?
4.5:1 for normal text, 3:1 for large text (18pt or 14pt bold). AAA requires 7:1 for normal text and 4.5:1 for large text.
How is contrast ratio calculated?
Using the WCAG formula: (L1 + 0.05) / (L2 + 0.05), where L1 is the relative luminance of the lighter colour and L2 is the darker. Relative luminance uses sRGB gamma correction.
Is AA always sufficient?
AA is the legal minimum in many jurisdictions but AAA improves readability for low-vision users. Aim for AAA on body text when possible.