Toolbench / Developer / Color Contrast Checker
Color Contrast Checker
Check text and background colours against WCAG accessibility standards.
Colours
Preview
Result
WCAG requires 4.5:1 for normal text (AA), 7:1 for AAA, and 3:1 for large text (18pt+ or 14pt bold).
About the color contrast checker
Contrast ratio measures how clearly text stands out from its background. It runs from 1:1 (identical, invisible) to 21:1 (black on white), and low contrast is one of the most common accessibility failures on the web.
The Web Content Accessibility Guidelines set thresholds: 4.5:1 for normal text at level AA, 7:1 at the stricter AAA, and 3:1 for large text since bigger letters are easier to read.
Meeting these levels helps people with low vision, colour blindness or simply a bright screen outdoors. The ratio here is calculated with the official WCAG relative-luminance formula.