Color Contrast Checker (WCAG)
Check colour contrast ratio against WCAG 2.1 AA and AAA standards. Pass/fail for normal and large text. Free.
How to use the Contrast Checker
WCAG contrast standards
AA (Level AA, the legal minimum in most countries): 4.5:1 for normal text, 3:1 for large text (18pt+ or 14pt bold+). AAA (enhanced): 7:1 for normal text, 4.5:1 for large. UI elements and icons need 3:1 minimum. Pure black on white is 21:1 (the max possible ratio).
Why contrast matters
Around 1 in 12 men and 1 in 200 women have some form of colour vision deficiency. Older eyes also lose contrast sensitivity. Designing for WCAG AA ensures your text is readable for as many people as possible — and it's a legal requirement under the UK's Equality Act 2010 and the US ADA for many public sites.
Frequently asked questions
What contrast ratio do WCAG 2.1 AA and AAA require?
AA requires at least 4.5:1 for normal text and 3:1 for large text. AAA requires 7:1 for normal text and 4.5:1 for large text.
What counts as large text?
Text of at least 18pt (24px) regular or 14pt (about 18.66px) bold.
Do logos and decorative elements need to pass?
Logos and purely decorative elements are exempt, but UI components and graphics needed to understand content should meet a 3:1 ratio.