WCAG Contrast Checker

Check whether a foreground / background colour pair meets WCAG 2 accessibility ratios. AA + AAA, normal + large text — instant in your browser.

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The quick brown fox jumps over the lazy dog
Smaller body text — read this carefully to check legibility.
AA · normal text (4.5:1)
AA · large text (3:1)
AAA · normal text (7:1)
AAA · large text (4.5:1)
Contrast ratio: —
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How to use the WCAG Contrast Checker

  1. 1
    Pick foreground + background
    The two colour swatches drive the live contrast calculation.
  2. 2
    Read the contrast ratio
    Ratios above 4.5:1 pass AA for normal text; 7:1 passes AAA.
  3. 3
    Adjust until all checks pass
    Nudge lightness on either colour to land in the safe zone.

WCAG contrast — the rules

WCAG 2 specifies minimum colour contrast ratios for legibility. AA (the de-facto standard) requires 4.5:1 for normal text and 3:1 for large text. AAA (stricter) requires 7:1 for normal and 4.5:1 for large.

'Large text' is 18pt or 14pt-bold and above. The contrast ratio is calculated from each colour's relative luminance, scaled (L_lighter + 0.05) / (L_darker + 0.05).

Frequently asked questions

Free?
Yes — no signup.
Which WCAG version?
WCAG 2.1 contrast ratios.
APCA?
This tool implements WCAG 2 contrast. The newer APCA standard isn't fully ratified yet.
Does it test images?
Just colour pairs. For image-text contrast use the image-tinted overlay approach.
Mobile?
Yes.

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