Colour contrast checker
Check text and background colours against WCAG AA and AAA contrast thresholds.
The quick brown fox
Readable forms work better for everyone.
Check the WCAG contrast ratio between text and background colours. See normal-text and large-text results while previewing the pair at once.
Relative luminance
sRGB colours are linearised and compared with the WCAG contrast formula.
Two thresholds
AA requires 4.5:1 for normal text and 3:1 for large text; AAA is stricter.
Frequently asked questions
What counts as large text?
WCAG defines it as at least 18pt regular or 14pt bold.
Does passing contrast guarantee accessibility?
No. Contrast is one requirement; typography, focus states, semantics and interaction still matter.
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