Color Contrast Checker
Check WCAG color contrast ratios between text and background colors with real AA and AAA pass or fail results — free, fast and private.
Sample text — The quick brown fox jumps over the lazy dog.
How to use Color Contrast Checker
- Pick a text color and a background color.
- Click Check Contrast to compute the real WCAG ratio.
- Read the AA and AAA pass or fail results for normal and large text.
- Adjust the colors until the combination passes.
Note: this tool runs in your browser. Nothing is uploaded.
Frequently Asked Questions
What is a good contrast ratio?
WCAG requires at least 4.5:1 for normal text (AA) and 7:1 for AAA. Large text needs 3:1 for AA and 4.5:1 for AAA.
How is the ratio calculated?
It uses the official WCAG formula based on the relative luminance of each color, so the result matches accessibility testing tools.
What is the highest possible ratio?
Black text on a white background scores 21:1, the maximum possible contrast ratio.
Is my data uploaded anywhere?
No. The calculation runs entirely in your browser.