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Color Contrast Checker

Check WCAG color contrast ratios

What is Color Contrast Checker?

Color Contrast Checker is a free online tool that helps you check wcag color contrast ratios. It runs entirely in your browser using client-side JavaScript, so your data stays private and never leaves your device.

When to Use

  • Quickly previewing CSS effects, colors, or layouts during design
  • Generating design assets like gradients, shadows, or color palettes
  • Checking accessibility compliance for colors and visual elements

How to Use

Enter your input in the field above, adjust any settings if available, and click the action button. Results appear instantly—no page reload, no server wait. All processing happens locally in your browser.

Related Tools

Try our Color Blindness Simulator for related functionality.

Deep Dive: How Color Contrast Checker Works

Color Contrast Checker bridges the gap between visual design and code implementation, helping designers and developers collaborate more effectively by providing instant visual feedback and code generation. The perennial challenge in web and UI development is translating visual design intent into precise CSS values—what looks right in a design tool may render differently across browsers, screen sizes, and color profiles. Color Contrast Checker provides interactive, real-time previews where you can experiment with visual properties and immediately see the result, then copy the exact production-ready CSS code. This tight feedback loop between visual manipulation and code output dramatically accelerates UI development workflows, reduces the iteration cycles of 'tweak value, rebuild, check' that slow down frontend work, and ensures consistency between design mockups and implemented interfaces.

Pro Tips

  • Always check contrast ratios with actual text on actual backgrounds—WCAG compliance is about real readability
  • Use the 60-30-10 rule for color distribution in UI design: 60% dominant, 30% secondary, 10% accent
  • Test color combinations under different lighting conditions and on different screens before finalizing

Common Mistakes to Avoid

  • Copying CSS without understanding which properties work together—can create unexpected interactions
  • Using em/rem units inconsistently—mixing units complicates responsive design

Frequently Asked Questions

How do I check if my text color and background meet WCAG accessibility standards?
Enter your text color and background color (HEX codes) into a color contrast checker. It calculates the contrast ratio and shows whether it passes WCAG 2.1 AA (minimum 4.5:1 for normal text) and AAA (minimum 7:1) accessibility requirements for users with visual impairments.
What contrast ratio do I need for large text vs normal text under WCAG rules?
WCAG AA requires 4.5:1 for normal text (under 18pt/24px) and 3:1 for large text (18pt+ bold or 24pt+ regular). WCAG AAA requires 7:1 for normal text and 4.5:1 for large text. These ratios ensure readability for users with moderate vision loss or color blindness.
How do I find accessible color combinations that meet contrast requirements?
A contrast checker typically suggests lighter or darker alternatives that meet accessibility thresholds. Start with your primary brand color and use the tool to find compliant text, background, and accent pairings. Many tools also simulate how colours appear with common types of color blindness.