Color Contrast Checker

Practical guide and verification

Use the threshold for the actual content type

WCAG contrast requirements differ for ordinary text, large text and non-text user-interface graphics. A pair that passes a 3:1 target may still fail normal body text, so choose the target that matches the real font size, weight and element role.

Check the rendered colors, including transparency

Semi-transparent foregrounds or backgrounds blend with what is behind them before the user sees a final color. A contrast calculation based only on the uncomposited source color can misrepresent the real ratio when alpha or layered backgrounds are involved.

Treat suggestions as starting points

A nearest passing color can preserve much of the original visual intent, but accessibility design also depends on states, focus indicators, disabled controls, gradients and surrounding context. Review the suggested color in the complete component rather than replacing a token blindly.

Do not use color contrast as the only accessibility test

Contrast does not evaluate semantics, keyboard access, screen-reader labels, motion, target size or color-only communication. Passing ratios are one necessary part of an accessible interface rather than a complete accessibility certification.

Record the tested pair and standard

When sharing evidence, include foreground, background, ratio, content type and the standard or threshold used. That makes the result reproducible and prevents a later reviewer from assuming that a pass for large text also applies to ordinary text.