Contrast Checker
Check WCAG color contrast ratios for accessibility compliance.
What is Contrast Checker?
A Contrast Checker is an accessibility tool that measures the contrast ratio between two colors — typically a foreground (text) color and a background color — and evaluates whether the combination meets the Web Content Accessibility Guidelines (WCAG). WCAG is the international standard for web accessibility, and it specifies minimum contrast ratios to ensure that text is readable for users with low vision, color blindness, or other visual impairments.
WCAG defines two conformance levels for contrast: AA (minimum) and AAA (enhanced). For normal-sized text, the AA standard requires a contrast ratio of at least 4.5:1, while AAA requires 7:1. For large text (18pt or 14pt bold and above), the thresholds are lower — 3:1 for AA and 4.5:1 for AAA. The contrast ratio is calculated based on the relative luminance of the two colors, a measure of perceived brightness that accounts for human vision's non-linear sensitivity to different wavelengths of light.
This tool is used by web designers, front-end developers, accessibility specialists, and product teams building applications that need to comply with WCAG, Section 508, or similar accessibility standards. Beyond compliance, good color contrast simply makes interfaces easier and more comfortable to use for everyone — not just users with disabilities.
How to Use Contrast Checker
- 1Step 1: Enter the foreground color — the color of your text or icon — in the first input field, using a HEX code, RGB values, or the integrated color picker.
- 2Step 2: Enter the background color — the color of the surface behind the text — in the second input field using the same format or color picker.
- 3Step 3: The tool instantly calculates and displays the contrast ratio as a number (e.g., 5.23:1), along with a preview of how the text looks against the background.
- 4Step 4: Check the WCAG compliance indicators to see whether your color pair passes or fails the AA and AAA standards for both normal text and large text sizes.
- 5Step 5: If the combination fails, adjust one or both colors — typically by darkening the foreground or lightening the background — until the contrast ratio meets your target WCAG level.
Benefits of Using Contrast Checker
- ✓WCAG Compliance: The tool directly tells you whether your color combination passes WCAG AA and AAA standards, giving you clear, actionable accessibility guidance.
- ✓Legal Risk Reduction: Many jurisdictions require web accessibility compliance — using a contrast checker helps ensure your product meets legal requirements like ADA and Section 508.
- ✓Better User Experience: High-contrast text is easier to read for all users, not just those with visual impairments — good contrast improves usability across lighting conditions and devices.
- ✓Instant Feedback: Real-time contrast ratio updates as you adjust colors mean you can iterate quickly toward accessible combinations without repeated manual checks.
- ✓Design Confidence: Knowing your chosen color pairs are accessible lets you finalize designs with confidence, reducing late-stage revisions triggered by accessibility audits.
- ✓Inclusive Design Practice: Building contrast checking into your workflow from the start cultivates a culture of accessibility-first design that benefits every user who encounters your product.
Example
About Contrast Checker
Contrast Checker calculates the contrast ratio between a foreground and background color and reports whether it meets WCAG 2.1 accessibility standards at AA and AAA levels. It's an essential tool for designers building accessible web interfaces. Enter HEX or RGB values for both colors.
- WCAG AA and AAA compliance check
- Shows contrast ratio numerically
- Foreground and background color inputs
- Pass/fail indicators for text sizes