Check WCAG 2.1 color contrast ratios instantly. Enter any foreground and background color to see if it passes AA (4.5:1) or AAA (7:1) — essential for accessible web design and legal compliance in many countries.
The WCAG contrast ratio measures the luminance difference between text and its background. WCAG 2.1 Level AA requires at least 4.5:1 for normal text and 3:1 for large text (18px+ or 14px bold). Level AAA requires 7:1. Relative luminance is calculated from RGB values using a standardized linearization formula — this tool applies it in real time as you pick colors. Meeting contrast requirements ensures content is readable for users with low vision and helps satisfy accessibility laws like the ADA, EN 301 549, and WCAG itself.