WCAG Color Contrast Checker Online
Sufficient color contrast is a WCAG 2.1 accessibility requirement for websites. The minimum AA level (4.5:1) is the standard for most commercial sites. AAA (7:1) is required for government and healthcare resources.
Frequently asked questions
What is WCAG?
Web Content Accessibility Guidelines is the international standard for web content accessibility. WCAG 2.1 defines minimum contrast ratios: AA = 4.5:1 for text, AAA = 7:1. Many countries legally require AA compliance.
What counts as large text?
Large text is 18pt (24px) or larger, or bold text at 14pt (18.67px) or larger. The AA threshold for large text is lower — 3:1 instead of 4.5:1 for normal text.
Does contrast affect SEO?
Not directly, but low contrast is flagged by Lighthouse as an accessibility issue. Google factors user experience quality into rankings — poor contrast degrades those signals.
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