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WCAG Color Contrast Checker

Check foreground and background color contrast ratios against WCAG AA and AAA accessibility standards.

Accessibility
Check color contrast ratios against WCAG guidelines to ensure accessible content.
WCAG AA & AAA Real-time preview Local calculation

Normal text (14pt) & Large Text (18pt)

This is a live preview of your chosen foreground and background colors. Adjust the inputs to see how readable your text will be for users.

Contrast Ratio 21.00 : 1
WCAG AA (Normal) 4.5:1 ratio PASS
WCAG AA (Large) 3.0:1 ratio PASS
WCAG AAA (Normal) 7.1:1 ratio PASS
WCAG AAA (Large) 4.5:1 ratio PASS

How ZeroData protects your privacy

  • ✓ No Uploads: Tool input is processed in your browser and is not sent to ZeroData servers.
  • ✓ No Storage: Tool input is not saved by this website.
  • ✓ No Input Tracking: Analytics never receive the text, files, keys, or credentials you process.
  • ✓ Verifiable: Disconnect from the network after the page loads; local tool processing continues without uploading your input.

How to Use the WCAG Color Contrast Checker

  1. Select a Foreground Color (the color of your text) using the visual color picker or by typing a HEX code.
  2. Select a Background Color (the color behind your text) using the visual color picker or by typing a HEX code.
  3. View the live text preview to visually assess the readability of your color combination.
  4. Check the Contrast Ratio output to see the exact mathematical score (e.g., 4.5:1 or 7.1:1).
  5. Review the Pass/Fail badges for WCAG AA and AAA standards across both normal and large text sizes.

Common Use Cases

  • Verifying brand color palettes against WCAG AA and AAA accessibility standards.
  • Checking the readability of text placed over colored buttons or call-to-actions.
  • Ensuring compliance with legal web accessibility requirements for government or educational sites.
  • Testing low-contrast "dark mode" themes for adequate legibility.
  • Auditing existing design systems to identify and correct inaccessible color combinations.

Frequently Asked Questions

What is a good contrast ratio?

WCAG AA requires a ratio of at least 4.5:1 for normal text and 3:1 for large text. AAA requires 7:1 and 4.5:1, respectively.

What qualifies as 'large text'?

Large text is typically defined as 18pt (24px) or 14pt (18.66px) if bold.

Does this tool support RGB or HSL inputs?

Currently, the tool is optimized for hexadecimal (Hex) color codes, which are standard in web development.

Is this tool checking my colors on a server?

No. All contrast calculations are performed locally in your browser to protect your proprietary design assets.

Why does contrast matter?

Sufficient contrast ensures that users with visual impairments, color blindness, or those in brightly lit environments can read your content.

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