Method & assumptions
How Color Contrast Checker derives its result.
Formula
Convert sRGB channels to relative luminance. Contrast ratio = (lighter luminance + 0.05) ÷ (darker luminance + 0.05).
Recommended workflow
- Enter foreground and background colors.
- Compare with the applicable threshold.
- Test hover, focus, disabled, and error states in the real interface.
Limitations
This is a numeric contrast aid, not a complete accessibility audit.
For important work, verify assumptions against the authoritative source for your task.