WCAG Contrast Checker
Check foreground/background contrast against WCAG AA and AAA text thresholds. Free, with no signup or usage-count limits.
Free · No signup · No watermark · On-device processing
Use the tool
Sample text · Aa 123
How to use WCAG Contrast Checker
- Enter opaque foreground and background HEX colours.
- Run the checker and review the sample text and contrast ratio.
- Read separate AA and AAA results for normal and large text.
How the result is calculated
The ratio uses WCAG relative luminance: (lighter + 0.05) / (darker + 0.05). Normal text needs 4.5:1 for AA and 7:1 for AAA. Large text needs 3:1 for AA and 4.5:1 for AAA. Pass/fail uses the unrounded ratio.
Large text means at least 18 pt regular or 14 pt bold. This checks a solid colour pair only; it does not certify an entire site or assess text on gradients, photographs or transparency.
Privacy and browser support
Your input is handled in this browser tab. Selected files and entered text are not sent to Varento Tools by this tool. Some specialized libraries load only when needed. A browser with JavaScript and sufficient device memory is required. Read our local-processing explanation.
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Frequently asked questions
Is this tool free without daily usage limits?
Yes. Varento Tools has no signup, accounts, usage-count caps, paywalls or watermarks. Device memory, format support and browser restrictions can still limit technically demanding files.
Does a pass mean my website is accessible?
No. Colour contrast is one part of accessibility. Font size, focus indicators, labels, keyboard access and many other requirements still need testing.
Is my input uploaded?
No. This tool processes your input in the current browser tab and does not send it to a processing server.
What are the practical limits?
Large text means at least 18 pt regular or 14 pt bold. This checks a solid colour pair only; it does not certify an entire site or assess text on gradients, photographs or transparency.