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Free Color Contrast Checker Online

A free color contrast checker calculates the WCAG contrast ratio between two colors instantly. Pick foreground and background colors, see AA and AAA pass/fail for normal and large text, and preview readability — no signup, runs in your browser.

Pick or type foreground and background colors and get an instant contrast ratio with WCAG AA and AAA compliance for normal and large text. Includes a live text preview so you can judge readability before shipping. Built with WCAG relative luminance formulas in plain JavaScript — free, no signup, fully client-side.

Contrast ratio

14.63:1

WCAG contrast compliance results
Text sizeWCAG AAWCAG AAA
Normal textbelow 18pt / 14pt boldPassPass
Large text18pt+ or 14pt+ boldPassPass

The quick brown fox jumps over the lazy dog.

Large heading preview

Runs 100% in your browser. Your data never leaves your device.

Uses WCAG 2.x relative luminance and contrast ratio formulas in plain JavaScript — all calculations run locally in your browser with no external libraries.

How to Use Color Contrast Checker

  1. Pick or enter a foreground (text) color
  2. Pick or enter a background color
  3. View the contrast ratio and WCAG AA/AAA pass/fail results
  4. Use the live preview to judge readability, then adjust colors as needed

When Would You Use This?

Designers validating brand palettes against WCAG before handoff can swap foreground and background colors and see AA/AAA compliance without leaving the browser.

Frontend developers auditing button, link, and body text colors against a design system catch failing combinations before they reach production.

Content teams checking hero banners and CTA blocks with custom backgrounds ensure headlines and supporting copy stay readable for all users.

Frequently Asked Questions

Is this contrast checker free to use?
Yes, completely free. No signup, no login, no payment ever.
Do I need to create an account?
No account needed. Open the tool and start picking colors immediately.
Is my data safe?
Everything runs in your browser. Nothing is uploaded to our servers. We cannot see your colors.
What WCAG levels does it check?
It checks WCAG 2.x contrast requirements for AA and AAA on both normal text (4.5:1 and 7:1) and large text (3:1 and 4.5:1). Large text is 18pt+ regular or 14pt+ bold.
How is the contrast ratio calculated?
We use the official WCAG relative luminance formula on sRGB channels, then compute (L1 + 0.05) / (L2 + 0.05) where L1 is the lighter color.

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