How to verify color contrast for accessibility?
Complete guide to verifying and optimizing color contrast according to WCAG standards. Tools, methods, and best practices.
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Web accessibility is no longer optional — it's a legal requirement in many countries and, above all, an ethical responsibility to all your users. Color contrast is one of the most fundamental criteria of visual accessibility.
Approximately 300 million people worldwide live with a visual impairment. Added to these are millions of users who browse the web in suboptimal conditions: phone screen in sunlight, reduced brightness to save battery.
This guide teaches you concrete methods to verify and correct your color contrasts.
Table of contents
How to do it in 3 steps
Open our contrast verification tool and enter your text and background colors.
Consult the displayed ratio and compliance level. Green = AA compliant. Yellow = large text only. Red = failed.
If the result is insufficient, use the suggested adjustments or manually modify colors until reaching at least 4.5:1.
Repeat for each text/background combination in your design. Document the results.
Complete with a colorblindness test using our simulator.
Pro tips
- If your design needs to support dark mode, ensure colors pass accessibility tests in both modes.
- Use non-color indicators (e.g., icons, bold text) to supplement color.
Common mistakes to avoid
- ✗Relying only on visual appearance without measuring contrast ratio.
- ✗Testing only one combination per page, forgetting states (hover, focus, disabled).
- ✗Neglecting 'secondary' texts (placeholders, captions, footnotes) which are often the most problematic.
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