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Accessibility tool
Colour contrast checker
Test two colours before they become an unreadable button, menu or paragraph. The calculator reports the contrast ratio and relevant WCAG thresholds.
Private by design. Your entries stay in this browser and are not sent to WebHostGB.
How the result is worked out
A useful guide, with the assumptions visible
The ratio is calculated from sRGB relative luminance using the WCAG formula, then compared with thresholds for normal and large text.
Common questions
About this colour contrast checker
What contrast does normal text need?
WCAG AA uses 4.5:1 for normal text and 3:1 for large text. AAA thresholds are higher.
Does placeholder text need contrast?
Text people need to read—including placeholder and disabled-state information—should remain distinguishable, though controls also have other requirements.
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