Free tool
Color Contrast & Accessibility Checker
Pick a foreground and background colour to check the WCAG contrast ratio and see whether your text passes AA and AAA for normal and large text.
Preview
The quick brown fox jumps over the lazy dog
Large heading 1234567890
Body copy at normal size shows whether everyday reading passes the threshold.
Contrast ratio
17.85:1
Comfortable for most readers
WCAG 2.1 results
Uses the official WCAG relative-luminance formula. “Large text” means 18pt+ (or 14pt+ bold). AA is the legal / accessibility-standard minimum; AAA is the enhanced target. All math runs in your browser.
Pick a foreground and background colour and see the exact WCAG 2.1 contrast ratio, plus whether your text passes AA and AAA for normal and large text. Uses the official relative-luminance formula, with a live preview so you can see the combination as your readers will. Everything runs in your browser.