Color Contrast Checker - WCAG AA & AAA Online
Color Contrast Checker
WCAG AA & AAA Accessibility Check
The quick brown fox jumps
Sample small text for large-text WCAG thresholds
Understanding WCAG Contrast Requirements
AA Normal Text
Requires a contrast ratio of at least 4.5:1 for regular body text.
AA Large Text
Text at 18pt (or 14pt bold) and larger only needs 3:1 — large text is easier to read at lower contrast.
AAA (Enhanced)
The stricter AAA level requires 7:1 for normal text and 4.5:1 for large text.
Local Processing
The ratio is computed entirely in your browser using the WCAG 2.1 relative luminance formula.
Why Contrast Matters
Low-contrast text is difficult or impossible to read for people with low vision, color blindness, or anyone using a screen in bright sunlight. WCAG's contrast ratio ranges from 1:1 (identical colors) to 21:1 (pure black on pure white) — meeting at least the AA level is a legal requirement in many jurisdictions for public-facing websites.
Key Takeaways
- 4.5:1 Minimum: The standard AA threshold for most body text.
- Relative Luminance: The ratio is based on perceived brightness, not just raw RGB difference.
- Client-Side Only: Your colors never leave your browser.