Color Contrast Checker
WCAG AA / AAA contrast, instantly.
Runs entirely in your browser — nothing you enter is uploaded, logged, or tracked.
Enter a text color and a background color to see their exact contrast ratio and whether it passes WCAG AA and AAA for normal and large text — with a live preview so you can nudge the colors until they pass.
Large text — the quick brown fox
Normal text — the quick brown fox jumps over the lazy dog. Pack my box with five dozen liquor jugs.
Frequently asked questions
What contrast ratio do I need?
WCAG AA requires 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1 and 4.5:1. “Large” is roughly 18.66px bold or 24px regular and up.
How is the ratio calculated?
From the relative luminance of each color using the official WCAG 2.1 formula (L1 + 0.05) / (L2 + 0.05), where L is luminance with the standard sRGB gamma correction.
Does it send my colors anywhere?
No — it is pure math done in your browser. Nothing is logged or uploaded.