Colour contrast checker.
Check whether your text and background colours meet the WCAG 2.2 accessibility standard. Low-contrast text is one of the commonest and easiest-to-fix accessibility failures — and it affects anyone with low vision, colour-blindness, or a screen in sunlight.
Large text preview (24px)
Normal body text preview. This is roughly the size most of your website's paragraphs will be, so this is the line that matters most for readability.
What the results mean
WCAG 2.2 sets two levels. AA is the standard almost every business should meet (and the legal benchmark in the UK): it requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (roughly 24px, or 18.66px bold). AAA is enhanced: 7:1 for normal text, 4.5:1 for large. Aim for AA everywhere; treat AAA as a bonus.
Two things this tool can't check for you: never rely on colour alone to convey meaning (a colour-blind visitor won't see it), and remember that real readability also depends on font size and weight. The full picture is in the accessibility guide.
Privacy: everything runs in your browser. Nothing is sent anywhere.