Utilities

Contrast ratio checker

Enter two colours and see the WCAG contrast ratio. Pass/fail for AA and AAA.

Foreground (text)

Background

Sample text for readability

Normal body text (14px) — AA requires 4.5:1, AAA requires 7:1

— contrast ratio

100% private. All processing happens locally in your browser — no files or data are ever sent to a server.

How to use Contrast ratio checker

01 Enter or select your colour using the controls above
02 Results update in real time — no button press needed
03 Use the Copy button to copy values to your clipboard

Frequently asked questions

Common questions about Contrast ratio checker.

Is Contrast ratio checker free to use?

Yes, Contrast ratio checker is completely free. No account, subscription, or payment is ever required — just open the page and start using it.

Does Contrast ratio checker upload my data to a server?

No. Contrast ratio checker runs entirely in your web browser using client-side JavaScript. Your files, text, and data never leave your device, making it 100% private.

Can I use Contrast ratio checker on my phone or tablet?

Yes. Contrast ratio checker is fully responsive and works on all modern smartphones, tablets, and desktop browsers without installing any app.

Does Contrast ratio checker work without an internet connection?

Yes. Once the page has loaded, Contrast ratio checker works fully offline — all colour processing is done locally in your browser.

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About Contrast ratio checker

Web Content Accessibility Guidelines (WCAG) require sufficient colour contrast between text and its background so people with low vision or colour blindness can read content. The Contrast Ratio Checker lets you enter two colours (foreground and background) and computes the luminance ratio — the same formula used by WCAG. It shows whether the pair passes AA (4.5:1 for normal text, 3:1 for large text) and AAA (7:1 for normal, 4.5:1 for large) at both levels. A live preview renders your colours side by side so you can judge readability at a glance.