Color Contrast Best Practices for Accessible Design

Understanding Contrast Ratios

Contrast ratio is a measurement of the difference in perceived luminance between two colors. It's expressed as a ratio from 1:1 (no contrast) to 21:1 (maximum contrast, black on white).

WCAG Requirements

• Normal text: Requires a contrast ratio of at least 4.5:1 (Level AA) or 7:1 (Level AAA)
• Large text (18pt+): Requires 3:1 (Level AA) or 4.5:1 (Level AAA)
• UI components: Interactive elements need 3:1 contrast against adjacent colors

Tools for Checking Contrast

Several excellent tools can help you verify contrast ratios:

• WebAIM Contrast Checker
• Colour Contrast Analyser (CCA)
• Browser DevTools (built-in contrast checkers)
• Figma and Adobe XD plugins

Design Tips

Start with high-contrast combinations and adjust carefully. Use darker shades for better contrast. Don't rely on color alone to convey information. Test your designs with different vision simulations.

Common Mistakes

Light gray text on white backgrounds, low contrast placeholder text, and colored links without additional indicators are frequent issues we see in audits.