Color · Free to use
Color Contrast Checker
Make sure your text is readable. Enter foreground and background colors to get the WCAG contrast ratio and whether it passes AA/AAA.
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How to use the contrast checker
- 1Set the text color and background color.
- 2Read the contrast ratio.
- 3Check the AA / AAA pass indicators for normal and large text.
This tool runs in your browser. The text, files and values you enter are not uploaded to our server.
About the contrast checker
A color contrast checker measures the WCAG contrast ratio between text and its background and tells you whether it passes accessibility levels AA and AAA. Low contrast fails real users and accessibility audits. Enter foreground and background colors to get the exact ratio and pass/fail for normal and large text.
Frequently asked questions
Is this tool free?
Yes — completely free, no signup, no watermark and no limits. Startup OG funds the site through its directory and partner program, not paywalled tools.
What contrast ratio passes WCAG?
Normal text needs ≥4.5:1 for AA and ≥7:1 for AAA. Large text (≈18pt, or 14pt bold) needs ≥3:1 for AA and ≥4.5:1 for AAA.
What counts as "large text"?
Roughly 18pt and up, or 14pt and up if bold. Large text is held to a lower contrast threshold because it is easier to read.
How is the contrast ratio calculated?
From the relative luminance of each color: (L_lighter + 0.05) ÷ (L_darker + 0.05), ranging from 1:1 to 21:1.