Color Contrast Checker
Check WCAG 2.1 AA and AAA contrast compliance for foreground and background colors.
Large Text Sample (24px Bold)
Normal body text sample — the quick brown fox jumps over the lazy dog.
Small text — WCAG requires ≥4.5:1 for AA compliance at this size.
| Standard | Normal Text (≥4.5) | Large Text (≥3) | UI Components (≥3) |
|---|---|---|---|
| AA | Pass | Pass | Pass |
| AAA | Pass | Pass | Pass |
What Is a Color Contrast Checker?
A color contrast checker calculates the luminance-based contrast ratio between two colors and evaluates it against WCAG 2.1 accessibility standards. The Web Content Accessibility Guidelines (WCAG) define minimum contrast ratios to ensure text is readable by people with low vision or color vision deficiencies.
How to Use
- Enter a foreground (text) color and background color as hex codes
- The contrast ratio and WCAG pass/fail results update instantly
- Use the color picker buttons to select colors visually
- The preview shows exactly how the text appears against the background
WCAG Contrast Requirements
- AA Normal Text: ≥ 4.5:1 — required for body text
- AA Large Text: ≥ 3:1 — text ≥18pt or bold ≥14pt
- AA UI Components: ≥ 3:1 — icons, borders, form inputs
- AAA Normal Text: ≥ 7:1 — enhanced accessibility standard
- AAA Large Text: ≥ 4.5:1 — enhanced for large text
FAQ
What counts as "large text" in WCAG?
Large text is defined as at least 18pt (24px) for regular weight, or at least 14pt (approximately 18.67px) for bold text. These sizes are considered large enough that lower contrast is acceptable.
Why does WCAG use luminance instead of perceived brightness?
The WCAG formula uses relative luminance computed in linear (gamma-decoded) sRGB space, weighted by human eye sensitivity: R×0.2126, G×0.7152, B×0.0722. This more accurately models how the human visual system perceives brightness differences.
Do I need to pass both AA and AAA?
AA compliance is the legal minimum for most accessibility standards (WCAG 2.1 Level AA). AAA is the enhanced standard and is recommended but not always required. Most organizations target Level AA as their baseline requirement.