What counts as large text?

Roughly 18pt regular or 14pt bold and up. Its contrast requirements are more relaxed.

How is the ratio calculated?

With the WCAG formula based on the relative luminance of the colors. The value ranges from 1:1 (no contrast) to 21:1 (black on white).

Why have AA and AAA levels?

AA is the baseline accessibility level most sites follow. AAA is stricter, for maximum readability.

Is data sent anywhere?

No, the calculation runs in your browser; nothing is sent to a server.

How do I fix text that fails the contrast check?

Darken the text or lighten the background (or vice versa) and watch the ratio rise until it passes AA or AAA.

Does contrast matter for accessibility and SEO?

Yes — readable contrast helps users with low vision and is part of accessibility best practice, which search engines reward indirectly through better usability.

Color contrast checker

Color contrast checker for WCAG: enter text and background colors to see the contrast ratio and whether the pair passes the AA and AAA levels. Check if text is readable on its background.

Sample of normal text

Large text

Text color

Background color

Contrast ratio

10.31 : 1

AA normal

✓ Pass

AA large

✓ Pass

AAA normal

✓ Pass

AAA large

✓ Pass

How to use it

1

Pick text and background colors

With the picker or by entering HEX codes.

2

Check the preview

The text is shown on the chosen background — readability is immediately visible.

3

Check the levels

The contrast ratio and AA/AAA marks for normal and large text.

Why it's useful

Contrast between text and background directly affects readability, especially for people with low vision. The WCAG accessibility standard sets minimum contrast ratios that matter both for usability and for site accessibility requirements.

This tool computes the contrast ratio with the WCAG formula and instantly shows whether a color pair passes the AA and AAA levels for normal and large text. The preview helps you judge the result by eye.

FAQ

Per WCAG, normal text needs at least 4.5:1 (level AA) or 7:1 (AAA). Large text needs 3:1 (AA) and 4.5:1 (AAA).

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