WCAG Color Contrast Checker

WCAG contrast requirements ensure text and UI elements are readable for people with low vision. AA standard requires 4

The calculator uses the standard published formula for color contrast wcag. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches, watts. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: Relative luminance = 0.2126R + 0.7152G + 0.0722B (linearised RGB). Each step in the calculation is shown so you can verify the result manually.