What contrast ratio passes WCAG?

Normal text needs at least 4.5:1 for AA and 7:1 for AAA. Large text (18pt+ or 14pt bold) needs 3:1 for AA and 4.5:1 for AAA.

How is the contrast ratio calculated?

It uses the WCAG formula: relative luminance is computed for each color, then the ratio is (lighter + 0.05) / (darker + 0.05), ranging from 1:1 to 21:1.

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Color Contrast Checker

Check WCAG color contrast between two colors.

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How to use the Color Contrast Checker

1Pick or paste a foreground (text) hex color.
2Pick or paste a background hex color.
3Read the contrast ratio and AA/AAA pass/fail badges.

About the Color Contrast Checker

Free WCAG color contrast checker. Enter foreground and background hex colors to get the contrast ratio and instant AA, AAA, and large-text pass/fail results with a live preview.

Part of our Color Tools collection. Browse all tools.

Frequently asked questions

What contrast ratio passes WCAG?: Normal text needs at least 4.5:1 for AA and 7:1 for AAA. Large text (18pt+ or 14pt bold) needs 3:1 for AA and 4.5:1 for AAA.
How is the contrast ratio calculated?: It uses the WCAG formula: relative luminance is computed for each color, then the ratio is (lighter + 0.05) / (darker + 0.05), ranging from 1:1 to 21:1.