Browse the Color & CSS station →
What does this tool do?
Contrast Checker: foreground color, background color, opaque backdrop → contrast ratio, normal text aa/aaa, large text aa/aaa, effective colors. Process locally in your browser. Inputs: Foreground color, Background color, Opaque backdrop. Outputs: Contrast ratio, Normal text AA/AAA, Large text AA/AAA, Effective colors.
How to use it?
Provide the listed input and choose Generate. Review the result, then copy or download where available. Clear removes inputs and results.
Browser-local processing. No uploads, content logging, persistence or remote resource loading. Generated markup is inert text; files are treated as untrusted data.
All color calculations use the documented sRGB color model and stay in this browser.
WCAG 2.x relative luminance is used. Alpha is composited against the explicit opaque backdrop; results are scoped to text contrast.