Free Tool
Color Contrast Checker
Check the WCAG contrast ratio between any two colours — everything runs in your browser, nothing is uploaded.
Large text sample
Normal body text sample — the quick brown fox jumps over the lazy dog.
Contrast ratio
21.00:1
AA normal
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AA large
—
AAA normal
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AAA large
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How this is calculated
Contrast ratio is calculated per the WCAG 2.x formula: relative luminance is computed for each colour, and the ratio between the lighter and darker luminance (plus 0.05) is taken. AA requires 4.5:1 for normal text and 3:1 for large text (18pt+, or 14pt+ bold). AAA requires 7:1 and 4.5:1 respectively.