The free Color Contrast Checker
Check the contrast ratio between text and background colours against WCAG 2.1 AA and AAA standards. See pass/fail for normal and large text and get.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Black on white → 21:1 (passes AAA) #777777 on white → 4.47:1 (fails AA for normal text, passes for large text)Open the Color Contrast Checker
Illustration. Open the tool for the real thing.
What is the Color Contrast Checker?
Good colour contrast makes text readable for everyone, including people with low vision or colour blindness and anyone using a phone in bright sunlight. The Web Content Accessibility Guidelines (WCAG) set minimum contrast ratios: 4.5:1 for normal text at AA level, 3:1 for large text, and 7:1 for normal text at the stricter AAA level.
Pick a text colour and a background colour and this tool calculates the contrast ratio exactly as WCAG defines it, shows a live preview, and reports pass or fail for AA and AAA for normal text, large text and user-interface components. A swap button flips the colours, and quick suggestions help you reach a passing ratio.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Relative luminance and contrast ratio per WCAG 2.1.
Pass/fail for normal text, large text and UI.
See how the text really looks.
Flip colours or tweak until you pass.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
How it compares
A plain look at this tool next to the usual alternative.
| This utility | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
What is a good contrast ratio?
At least 4.5:1 for normal text and 3:1 for large text (WCAG AA). 7:1 is AAA.
What counts as large text?
18 pt (24 px) or 14 pt (about 18.7 px) bold and above.
Does contrast matter for SEO?
Accessibility is part of page experience and helps user engagement.
What is the maximum ratio?
21:1, black on white.
Is WCAG a legal requirement?
In many countries accessibility standards apply to public and commercial sites.
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