What is WCAG AA contrast? The 4.5:1 ratio requirement explained for body text
WCAG AA requires a minimum contrast ratio of 4.5:1 for normal text (under 18pt or 14pt bold) against its background. This is the legal accessibility standard in most jurisdictions (Section 508 in the US, EN 301 549 in the EU) and the minimum bar every website should clear.
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Contrast Checker
Check color contrast for accessibility.
Large Text
Normal text sample.
How this is calculated
A contrast ratio of 4.5:1 means the lighter color is 4.5 times as bright as the darker color, as measured by the WCAG relative luminance formula. Pure black (#000000) on pure white (#FFFFFF) has a ratio of 21:1, the maximum. A medium gray (#767676) on white has a ratio of exactly 4.5:1, barely passing. Designers often push body text lighter for aesthetic reasons ("it looks cleaner"), but anything below 4.5:1 is literally unreadable for users with low vision, color blindness, or in bright ambient light.
Verdict
Always meet WCAG AA for body text. It's not aspirational; it's the floor. Use a contrast checker during design, not as an afterthought. If your brand palette doesn't have accessible text-background pairings, create accessible variants for your digital products.