HTML Tools
Colour Contrast Checker
Check the contrast ratio between a foreground and background colour pair against WCAG 2.1 accessibility guidelines. Shows pass/fail results for all four criteria: AA Normal, AA Large, AAA Normal and AAA Large. Includes a live text preview.
About the Colour Contrast Checker
Checks foreground/background colour pairs against the WCAG 2.1 accessibility guidelines. Shows the contrast ratio and pass/fail status for all four WCAG criteria.
Large text means 18pt (24px) or larger, or 14pt (18.67px) and bold. All other text is normal. AA compliance is the minimum legal requirement in many jurisdictions.
Contrast ratio is calculated per the WCAG algorithm: relative luminance of the lighter colour divided by the relative luminance of the darker colour, plus 1.
Frequently asked questions
What is the minimum contrast ratio for WCAG AA?
WCAG 2.1 Level AA requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (18pt/24px or 14pt/18.67px bold). Most web accessibility legislation requires AA compliance as a minimum.
What counts as large text?
Large text is defined as 18pt (24px) or larger in normal weight, or 14pt (18.67px) or larger in bold weight. For all other text the normal-text contrast thresholds apply.