Color Contrast Checker (WCAG)
Check text and background contrast for accessibility · free, no signup
Free Color Contrast Checker — WCAG AA and AAA Accessibility
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.
Key features
Exact WCAG maths
Relative luminance and contrast ratio per WCAG 2.1.
AA and AAA results
Pass/fail for normal text, large text and UI.
Live preview
See how the text really looks.
Swap and adjust
Flip colours or tweak until you pass.
How to use it
- Choose the text (foreground) colour.
- Choose the background colour.
- Read the contrast ratio and the pass/fail badges.
- Adjust colours until you pass the level you need.
Worked example
Example
Black on white → 21:1 (passes AAA) #777777 on white → 4.47:1 (fails AA for normal text, passes for large text)
Who uses this tool
Web designers
Check palettes before handing over designs.
Developers
Verify accessibility compliance.
Content teams
Make sure banners and buttons are legible.
Tips for the best results
- Aim for at least 4.5:1 for body text.
- Do not rely on colour alone to convey meaning.
- Test on both light and dark modes.
- Increase font weight or size if contrast is borderline.
Common mistakes to avoid
- Testing only the main text and forgetting link and button states.
- Assuming dark grey on white always passes.
- Ignoring text over images and gradients.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
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.
Is it free?
Yes.