Colour Contrast Checker
Test any colour combination against WCAG 2.1 standards. See how your colours appear to users with colour vision deficiency — instantly, free, in your browser.
Normal colour vision
How this combination looks with colour vision deficiency
protanopia
Ratio: 17.93:1 ✓ AA
deuteranopia
Ratio: 17.93:1 ✓ AA
tritanopia
Ratio: 17.93:1 ✓ AA
Understanding colour contrast and accessibility
WCAG Contrast Standards
The Web Content Accessibility Guidelines (WCAG) define minimum contrast ratios to ensure text is readable for users with low vision or colour blindness:
- 4.5:1 WCAG AA — Normal text (under 18pt)
- 3.0:1 WCAG AA — Large text (18pt+ or 14pt bold)
- 7.0:1 WCAG AAA — Normal text (enhanced)
- 4.5:1 WCAG AAA — Large text (enhanced)
Why CVD simulation matters
Approximately 8% of men and 0.5% of women have some form of colour vision deficiency. Even if your colour combination passes WCAG contrast ratios for normal vision, it may fail for users with protanopia or deuteranopia — who see reds and greens very differently. Always test your designs with CVD simulation.