Contrast Checker - WCAG Accessibility Tool
Check if your text and background colors meet WCAG accessibility standards. Instant results, no signup.
Understanding Color Contrast and Accessibility
Color contrast is the difference in brightness between your text and its background. Low contrast means people struggle to read your content. This affects everyone, not just people with vision impairments. Think about reading your phone in direct sunlight, or squinting at light gray text on a white background. A contrast checker WCAG tool like this one helps you verify that your color pairings meet the standards set by the Web Content Accessibility Guidelines.
What do the WCAG levels mean?
WCAG (Web Content Accessibility Guidelines) defines two compliance levels for text contrast. These guidelines are maintained by the W3C and are the global standard for web accessibility. You can read the full specification in the W3C WCAG 2.1 Understanding Contrast documentation.
- AA is the standard most websites should meet. It requires a contrast ratio of 4.5:1 for normal text and 3:1 for large text (18px bold or 24px regular).
- AAA is the highest standard. It requires 7:1 for normal text and 4.5:1 for large text. Harder to achieve but worth aiming for.
How contrast ratios are calculated
The contrast ratio between two colors is determined by their relative luminance values. Relative luminance measures the perceived brightness of a color, accounting for the fact that human eyes are more sensitive to green light than red or blue. The formula produces a ratio between 1:1 (no contrast, identical colors) and 21:1 (maximum contrast, black on white). When you use a contrast checker WCAG tool, this calculation happens automatically so you can focus on design decisions rather than math.
Why does this matter?
About 1 in 12 men and 1 in 200 women have some form of color vision deficiency. Add in aging eyes, screen glare, and low-quality displays, and poor contrast affects a huge portion of your audience. Beyond individual users, many countries now require WCAG AA compliance as a legal standard for public-facing websites. In the United States, the ADA has been interpreted to cover web accessibility, and the European Accessibility Act sets similar requirements across the EU. Good contrast is good design, and increasingly, it is a legal obligation.
Tips for better contrast
- Dark text on light backgrounds almost always works better than the reverse for body text
- Avoid pure black (#000000) on pure white (#FFFFFF). It's technically high contrast but can cause eye strain. Slightly off-black on slightly off-white is easier to read
- Test your colors on multiple screens. What looks fine on your calibrated monitor might be invisible on a cheap laptop
- Don't rely on color alone to convey information. Use icons, labels, or patterns alongside color
- Check contrast for all text sizes on your page, not just body text. Navigation links, captions, and placeholder text are often overlooked
- When designing with brand colors, establish accessible pairings early. It is much easier to build accessibility into a design system from the start than to retrofit it later