What's the difference between AA and AAA compliance?

AAA is a stricter standard requiring a higher contrast ratio than AA — AA is the more commonly targeted baseline, while AAA is recommended for content where accessibility is especially critical.

Does text size affect the required contrast ratio?

Yes, WCAG allows a lower contrast ratio for large text than for normal-size text, since larger text is inherently easier to read at lower contrast.

What happens if my colors fail the check?

Adjust one or both colors' lightness until the ratio passes — the tool shows you the ratio updating live as you experiment with different values.

Does WCAG Contrast Checker upload my files to a server?

No. WCAG Contrast Checker runs entirely in your browser using on-device processing, your files never leave your device.

WCAG Contrast Checker

Check the contrast ratio between two colors against WCAG AA/AAA thresholds.

Runs in your browser

Foreground (text)

Background

Large sample text

Normal sized sample text for contrast checking.

17.40:1

AA, normal text (4.5:1)

AA, large text (3:1)

AAA, normal text (7:1)

AAA, large text (4.5:1)

About this tool

WCAG accessibility guidelines require a minimum contrast ratio between text and background colors, and that ratio is a specific calculated number, not something you can reliably judge just by looking at two colors next to each other. This tool checks the contrast ratio between two colors against WCAG AA/AAA thresholds, giving you a definitive pass/fail against the actual accessibility standard instead of a subjective visual judgment.

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