OhMyCalc

Color Contrast Calculator

Check foreground/background color contrast ratio against WCAG 2.1 AA and AAA compliance levels.

How to Use the Color Contrast Calculator

  1. Enter foreground RGB values (0-255).
  2. Enter background RGB values (0-255).
  3. Click Calculate.
  4. Check WCAG AA and AAA pass/fail results.

Casos de Uso

Fórmula

Ratio = (L1 + 0.05) / (L2 + 0.05) where L = relative luminance

Perguntas Frequentes

How accurate is this calculator?
Results are based on standard industry formulas and are suitable for preliminary estimates.
What units are used?
Standard IT units (requests/sec, ms, %, USD) are used unless otherwise noted.
Is it free?
Yes, all calculators are completely free.