Real-Time Calculation
Contrast ratios update instantly as you pick colors — no page reload needed.
WCAG 2.1 Compliance
Tests against all four WCAG levels: AA and AAA for both normal and large text.
Smart Suggestions
When a combo fails, get the nearest passing color alternatives automatically.
Multi-Format Input
Enter colors in HEX, RGB, or HSL — all formats sync bidirectionally.
Frequently Asked Questions
What is a WCAG contrast ratio?
The WCAG contrast ratio measures the difference in luminance between foreground and background colors. It ranges from 1:1 (no contrast) to 21:1 (maximum contrast, black on white). Higher ratios mean better readability for people with low vision or color vision deficiencies.
What's the difference between AA and AAA?
WCAG AA is the minimum compliance level required for most websites and legal accessibility standards. AAA is the enhanced, highest level. AA requires 4.5:1 for normal text and 3:1 for large text. AAA requires 7:1 for normal text and 4.5:1 for large text.
What counts as "large text"?
WCAG defines large text as 18pt (24px) or larger, or 14pt (18.66px) bold or larger. Large text has lower contrast requirements because the increased size or weight compensates for reduced contrast, maintaining readability.