Free Tool

Free Color Contrast Checker

A color contrast checker tests whether foreground and background color pairs meet WCAG 2.2 accessibility requirements. Enter two hex colors to calculate the contrast ratio instantly, or scan any URL to find every contrast failure on the page. This tool combines manual color pair checking with full-page scanning powered by axe-core and AI visual analysis. If you spell it colour contrast checker, this is the same tool: the WCAG thresholds are identical in every region.

Low contrast text is the most common accessibility failure on the web. The WebAIM Million 2026 report found it on 83.9% of the top one million home pages, up from 79.1% in 2025, with an average of 34 distinct low-contrast instances per page. It has ranked as the single most common WCAG failure for seven consecutive years.

WCAG Contrast Requirements

WCAG 2.2 Level AA requires a minimum contrast ratio of 4.5:1 for normal text (under 18pt or under 14pt bold) and 3:1 for large text (18pt or 14pt bold and above). Non-text UI components like icons, borders, and form controls require 3:1 contrast under WCAG 1.4.11. Level AAA raises the bar to 7:1 for normal text and 4.5:1 for large text.

Frequently Asked Questions

What contrast ratio is required for WCAG AA? WCAG 2.2 Level AA requires a minimum contrast ratio of 4.5:1 for normal text (under 18pt or under 14pt bold) and 3:1 for large text (18pt or 14pt bold and above). Non-text UI components like icons, borders, and form controls also require 3:1 contrast against adjacent colors under WCAG 1.4.11.

How do I test color contrast on my website? Enter two hex color values above to calculate their contrast ratio instantly, or enter a URL to scan the entire page for WCAG contrast failures. The URL scanner uses axe-core automated testing plus AI visual analysis to catch contrast issues that rule-based scanners miss, including text over images and gradients.

What is the difference between AA and AAA contrast? WCAG AA requires 4.5:1 for normal text and 3:1 for large text. WCAG AAA raises the bar to 7:1 for normal text and 4.5:1 for large text. AA is the standard referenced by ADA, Section 508, and the European Accessibility Act. AAA is aspirational and not required by most regulations.

Does this check contrast on images and gradients? The manual color pair checker tests two solid colors. The URL scanner goes further: axe-core checks computed text-to-background contrast ratios, and the AI visual analysis layer evaluates text over images, gradients, and complex backgrounds where automated tools cannot determine the background color.

Is this color contrast tester free? Yes. The manual color pair checker is completely free with no limits. The URL scanner allows up to 3 free scans per day with no account required. Install the Chrome extension for unlimited contrast and accessibility scanning across localhost, staging, and production.

How does this compare to WebAIM's contrast checker? WebAIM's contrast checker tests one color pair at a time. This tool does that plus scans entire web pages for every contrast failure at once. The URL scanner uses axe-core for precise text contrast ratios and adds AI visual analysis for non-text contrast (icons, borders, form controls) that WebAIM and similar manual tools do not check.

Is this a colour contrast checker or a color contrast checker? Both. It is the same tool whichever spelling you use. "Colour contrast checker" is the British, Australian, Canadian, and Irish spelling; "color contrast checker" is the American one. The WCAG 2.2 specification uses American spelling in its normative text, so success criteria such as 1.4.3 Contrast (Minimum) are named identically in every region. The ratios you must hit are also identical worldwide: 4.5:1 for normal text, 3:1 for large text and UI components.

What is a good contrast ratio? Aim for 4.5:1 or higher on normal body text, which clears WCAG AA. Anything at or above 7:1 also clears AAA, the enhanced standard. Below 3:1, text is difficult to read for most users with low vision and fails every level. Pure black on white is 21:1, the maximum possible ratio.

Last updated July 29, 2026