---
title: "WCAG Colour Contrast Checker | formformform"
description: "Calculate a colour contrast ratio and check WCAG AA and AAA requirements for normal and large text."
url: "https://www.formformform.com/tools/colour-contrast-checker"
type: static
generatedAt: "2026-08-23T18:56:58.727Z"
---
# Colour contrast checker

Check text and background colours against WCAG AA and AAA contrast thresholds.

Text colour

Background colour

The quick brown fox

Readable forms work better for everyone.

Check the WCAG contrast ratio between text and background colours. See normal-text and large-text results while previewing the pair at once.

## Relative luminance

sRGB colours are linearised and compared with the WCAG contrast formula.

## Two thresholds

AA requires 4.5:1 for normal text and 3:1 for large text; AAA is stricter.

## Frequently asked questions

What counts as large text?

WCAG defines it as at least 18pt regular or 14pt bold.

Does passing contrast guarantee accessibility?

No. Contrast is one requirement; typography, focus states, semantics and interaction still matter.

## Other free tools

-   [Form accessibility checker](https://www.formformform.com/tools/form-accessibility-checker)
    
    Audit form HTML for labels, grouping, instructions and common keyboard or error-message problems.
    
-   [HTML input pattern generator](https://www.formformform.com/tools/html-input-pattern-generator)
    
    Build and test HTML pattern validation with live matching examples and ready-to-copy attributes.
    
-   [Form endpoint tester](https://www.formformform.com/tools/form-endpoint-tester)
    
    Preview the GET URL or POST payload a form would send, without making a network request.
    

## Want the form to collect the answers too?

Hand-written HTML still needs somewhere to post to. formformform gives you the form, the hosting, the responses and the notifications — free while we are in early access.

[Start free](https://app.formformform.com/register?utm_source=landing&utm_medium=bottom&utm_campaign=tools&utm_content=colour-contrast-checker)