Color Pairs
One foreground,background hex pair per line.
WCAG Contrast Results
Enter color pairs to check WCAG contrast ratios.
How to Use
Enter one foreground/background hex color pair per line (e.g. #000000,#FFFFFF). For each pair, the tool computes the WCAG 2.x relative luminance of both colors using the standard sRGB-to-linear transform, then the contrast ratio between them ((L1+0.05)/(L2+0.05), lighter over darker). Each row shows a live swatch preview, the exact ratio to two decimal places, and pass/fail against all four WCAG thresholds: AA normal text (4.5:1), AA large text (3:1), AAA normal text (7:1), and AAA large text (4.5:1). Pure black on white computes to the textbook 21.00:1 maximum ratio.