Contrast Checker
Free online contrast checker. No sign-up, no installation. Runs entirely in your browser.
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Formula: (L1 + 0.05) / (L2 + 0.05), where L = relative luminance
What is a Contrast Checker?
A contrast checker is a tool that measures the difference between foreground and background colors to ensure they meet Web Content Accessibility Guidelines (WCAG) standards. Proper color contrast is essential for people with visual impairments, color blindness, and those viewing content on low-quality displays or in bright sunlight.
This tool calculates the relative luminance of your colors and displays the contrast ratio, helping you verify compliance with WCAG AA and AAA accessibility standards.
How to Use the Contrast Checker
- Select Foreground Color: Choose the text or element color using the color picker or enter a hex code.
- Select Background Color: Choose the background color where the text appears.
- View Results: The tool instantly displays the contrast ratio and WCAG compliance status.
- Check Preview: See a live preview of your color combination in the preview box.
- Swap Colors: Use the swap button to quickly reverse foreground and background.
- Get Suggestions: If contrast fails, view suggested accessible color alternatives.
Common Use Cases
- Web Design: Ensure your website colors meet accessibility standards before launch.
- UI/UX Design: Verify button, link, and text colors pass WCAG requirements.
- Marketing Materials: Create accessible emails, presentations, and documents.
- Compliance Testing: Audit existing designs for accessibility compliance.
- Brand Guidelines: Establish color palettes that are both accessible and on-brand.
- Data Visualization: Ensure chart colors are distinguishable for all users.
What is WCAG?
WCAG (Web Content Accessibility Guidelines) is an international standard created by the World Wide Web Consortium (W3C) to make web content more accessible to people with disabilities. WCAG AA is the standard most organizations aim for, while AAA is the highest level of accessibility.
What does a contrast ratio of 4.5:1 mean?
A contrast ratio of 4.5:1 means the lighter color is 4.5 times brighter than the darker color. This ratio is the WCAG AA standard for normal text. Higher ratios (like 7:1) provide even better accessibility and meet the WCAG AAA standard.
Why does text size matter for contrast?
Larger text is easier to read even with lower contrast. WCAG allows a 3:1 ratio for large text (18pt or 14pt bold) versus 4.5:1 for normal text. This tool checks both standards.
What is relative luminance?
Relative luminance is a measure of how bright a color appears on a scale from 0 (darkest) to 1 (brightest). It’s calculated using the WCAG formula that accounts for how human eyes perceive different colors, with green appearing brighter than red or blue at the same intensity.
Can I use this tool for print materials?
While this tool is designed for digital content, the contrast principles apply to print as well. However, print materials may have different accessibility requirements, so consult print-specific guidelines for your region.
How do I make colors more accessible?
To improve contrast, either darken your text color or lighten your background (or both). You can also use this tool’s suggestion feature to find similar colors with better contrast. Avoid relying solely on color to convey information; use text labels or patterns instead.
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Frequently Asked Questions
Q: What is WCAG color contrast?
WCAG (Web Content Accessibility Guidelines) color contrast refers to the difference in brightness between text and its background. The guidelines set minimum contrast ratios to ensure text is readable for people with low vision or color blindness. WCAG 2.1 specifies different levels: AA (4.5:1 for normal text) and AAA (7:1 for normal text).
Q: How do I use the Color Contrast Checker?
Simply enter your foreground (text) color and background color using hex codes, RGB values, or by clicking the color pickers. The tool will instantly calculate the contrast ratio and display whether your color combination meets WCAG AA, AAA, or neither standard. You’ll also see a preview of how your text appears with the selected colors.
Q: What’s the difference between WCAG AA and AAA?
WCAG AA is the minimum recommended standard for most web content, requiring a 4.5:1 contrast ratio for normal text. WCAG AAA is a higher standard requiring 7:1 contrast ratio and is recommended for specialized content or when maximum accessibility is needed. AAA compliance automatically meets AA requirements.
Q: Why is color contrast important?
Adequate color contrast is essential for web accessibility. It helps people with visual impairments, color blindness, and those viewing content on poor-quality displays read text more easily. Good contrast also improves readability for all users, including those viewing content in bright sunlight or on mobile devices.
Q: Can I check contrast for different text sizes?
Yes! WCAG has different contrast requirements based on text size. Large text (18pt or larger, or 14pt bold or larger) requires a 3:1 ratio for AA compliance, while normal text requires 4.5:1. Our tool allows you to specify text size to ensure you’re meeting the appropriate standard for your specific use case.
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