Understand the result
Why contrast matters
Low contrast makes text and controls harder to perceive, especially on mobile screens, dim displays, bright environments, and for people with low vision. Contrast checks should happen before a design system reaches production rather than after accessibility problems are reported.
How to read the result
WCAG AA requires a 4.5:1 ratio for normal text and 3:1 for large text. AAA is stricter at 7:1 for normal text and 4.5:1 for large text. Meaningful non-text interface components have a separate 3:1 contrast requirement.
Test the actual interface colors
Use the exact foreground and background values from the component you are reviewing. Test important states separately, including hover, focus, disabled, error, and selected states where color communicates information.
What a contrast score does not prove
A passing pair does not prove the whole page is accessible. Font size, background images, focus indicators, keyboard order, motion, form labels, semantic structure, and screen-reader behavior still need review.