WCAG Color Contrast Checker — Free Online Tool

What Is WCAG Color Contrast Checker?

A free online WCAG color contrast checker. Enter foreground and background colors to check compliance with WCAG 2.1 AA and AAA standards for normal and large text. Includes preset color pairs and a live preview.

Color contrast is one of the most overlooked aspects of web accessibility, yet it directly impacts whether millions of users can read your content. WCAG (Web Content Accessibility Guidelines) 2.1 defines specific contrast ratios for text and background colors to ensure readability for users with low vision, color blindness, or viewing conditions like bright sunlight. Color Contrast Checker measures any foreground/background color combination against these standards and tells you instantly whether it passes or fails.

Enter colors using the HEX color picker or type hex values directly. The tool calculates the contrast ratio — a number between 1:1 (no contrast) and 21:1 (maximum contrast, black on white). The result is compared against four WCAG thresholds: AA normal text (4.5:1), AA large text (3:1), AAA normal text (7:1), and AAA large text (4.5:1). Each threshold shows a clear pass or fail indicator, so you know exactly which standards your color pair meets.

A live preview panel shows sample text rendered with your chosen colors, giving you a visual check alongside the numeric analysis. This is important because some color combinations that pass mathematically may still look uncomfortable to read (or vice versa). Eight preset color pairs are included for common scenarios — dark mode, light mode, link colors, and warning badges — so you can test real-world combinations quickly.

The tool also handles edge cases. If the colors are too similar, the ratio drops below 3:1 and all checks fail — a strong signal that the pair is unusable for text. If you are testing for non-text elements like icons or form borders, the WCAG non-text contrast requirements are more lenient (3:1 minimum), which this checker can help you evaluate visually even though the primary thresholds target text.

Real-World Use Cases for WCAG Color Contrast Checker

Ensuring Text Readability on a Landing Page

Your designer chose light gray text (#999) on a white background for the hero section. Test it here: the ratio is approximately 2.8:1 — it fails WCAG AA for all text sizes. Adjust the foreground to a darker gray (#595959) and retest until it passes AA for normal text (4.5:1+). The live preview confirms readability at a glance.

Validating Dark Mode Color Schemes

A dark mode UI uses white text on a dark blue background. Test the combination: white (#FFFFFF) on navy (#0A1628) typically yields a ratio above 10:1, passing AAA easily. However, the link color in dark mode might be too subtle — test your blue link (#4A90D9) on the same dark background to verify it meets at least AA for large text.

Selecting Accessible Button and Badge Colors

Your notification badge uses white text on a red background. Test the exact red shade — not all reds pass contrast requirements. A bright red (#E53E3E) with white text usually passes AA for large text but may fail for small badge labels. Adjust the red shade and retest until the badge is both on-brand and accessible.

Why Use WCAG Color Contrast Checker?

WCAG 2.1 AA and AAA compliance for normal and large text
Live text preview with your color combination
8 preset color pairs for common scenarios
Clear pass/fail indicators with required ratios

How to Use WCAG Color Contrast Checker — Step by Step

Enter foreground (text) and background colors.

View the contrast ratio and WCAG compliance results.

Use preset color pairs for common scenarios.

Adjust colors until all checks pass.

Who Is WCAG Color Contrast Checker Best For?

web accessibility
UI design
WCAG compliance
color selection

Pro Tips for WCAG Color Contrast Checker

1Design for AA compliance as the minimum standard. AAA is ideal but not required for all content — reserve AAA for long-form reading contexts where readability is critical.
2Large text (18px+ regular or 14px+ bold) has a lower contrast requirement (3:1 for AA). Use this to your advantage for headlines, buttons, and labels that can be styled larger.
3Never rely on color alone to convey information. Even with passing contrast, users with color blindness need additional cues like icons, underlines, or labels to distinguish states.
4Test color pairs early in the design process rather than after development. Fixing contrast issues in CSS is easy; fixing them after a brand color has been finalized is much harder.

WCAG Color Contrast Checker — Frequently Asked Questions

What is WCAG 2.1 AA compliance?

WCAG AA requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (18pt or 14pt bold).

What is the difference between AA and AAA?

AAA is a higher standard requiring 7:1 for normal text and 4.5:1 for large text. AAA is not required for all content but is recommended where possible.

Will the generated CSS work in all browsers?

The CSS generators produce W3C-standard code that works in Chrome, Firefox, Safari, and Edge. Vendor prefixes are included where needed for older browser versions.

Can I copy the generated code directly?

Yes. Each generator provides a copy button that places the code on your clipboard. The code is ready to paste into your project — no cleanup or modification needed.

Is WCAG Color Contrast Checker really free to use?

Yes, WCAG Color Contrast Checker is completely free with no hidden charges, no usage limits, and no premium tiers. You can use it as often as you need without signing up or providing any personal information.

Ready to Use WCAG Color Contrast Checker?

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