Contrast

WCAG Contrast Checker

Pick a text color and a background color to see the WCAG contrast ratio and whether it passes AA and AAA for normal and large text, with a live preview.

Colors

Local
The quick brown fox jumps over the lazy dog.

Result

Contrast ratio
AA — normal text
AA — large text
AAA — normal text
AAA — large text
About this tool

About Contrast Checker

The Contrast Checker measures the WCAG contrast ratio between a text color and a background, and reports whether it passes AA and AAA for normal and large text. It is essential for designers and developers building accessible interfaces.

Readable color combinations are a legal and usability requirement. Checking the ratio locally gives an instant pass or fail against the official thresholds while you design.

How to use

Step by step

  1. Choose a text color and a background color.
  2. The contrast ratio is calculated and shown with a live preview.
  3. Read the AA and AAA results for both normal and large text.
  4. Adjust either color until the combination passes the level you need.
Key features

What it offers

  • WCAG contrast ratio
  • AA and AAA pass indicators
  • Foreground and background pickers
  • Checked on your device
Best practices

Tips for best results

  • Aim for at least AA (4.5:1 for normal text); treat AAA as a stronger target.
  • Large or bold text has a lower threshold, but do not rely on that for body copy.
  • Check both light and dark themes if your interface supports them.
Benefits

Why people use it

WCAG thresholds

Reports AA and AAA results for normal and large text.

Live preview

See the actual text-on-background pairing as you tune it.

Accessibility-focused

Helps meet real readability requirements.

Local

Color values stay in your browser.

FAQ

Common questions

WCAG contrast ranges from 1:1 (no contrast) to 21:1 (black on white). Higher ratios are easier to read.
AA requires at least 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1 and 4.5:1 respectively.
Large text is roughly 18pt (24px) regular or 14pt (18.66px) bold and above.
No. The contrast is calculated entirely in your browser.
Private by design

This runs entirely in your browser

No file or text you enter here is uploaded. Encoding and decoding happen on your device using native browser APIs — close the tab and nothing remains on a server.

Install Toolisco Add it to your device for offline, one-tap access.