WCAG color contrast checker
Pick a text colour and a background colour to get the contrast ratio and check whether it passes the WCAG AA and AAA thresholds for normal and large text. Everything runs in your browser.
The quick brown fox jumps over the lazy dog
Small text sample at 16px.
Contrast ratio: -
What the levels mean
WCAG defines contrast thresholds so text stays readable. AA is the common legal baseline: 4.5:1 for normal text, 3:1 for large text (18.66px bold or 24px+). AAA is stricter: 7:1 and 4.5:1. Large text needs less contrast because thicker strokes are easier to read.
The ratio is computed from the WCAG 2 relative-luminance formula. It checks the two colours you enter; real pages should also be tested with the text actually rendered.