Free Online Color Contrast Checker (WCAG) - ATools

Free online color contrast checker for WCAG 2.1 AA/AAA with pass/fail results, suggestions, and simple color-blind simulation. Runs locally.

Check WCAG contrast ratio for foreground/background colors (local only, no uploads).

ForegroundBackgroundColor-blind simulation

Sample text

The quick brown fox jumps over the lazy dog. 0123456789

Results

Contrast ratio: 17.85

AA (normal text) ≥ 4.5PASS

AA (large text) ≥ 3.0PASS

AAA (normal text) ≥ 7.0PASS

AAA (large text) ≥ 4.5PASS

Suggested foreground

Use black: 21.00Use white: 1.00