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Contrast Ratio Calculator

Compute WCAG contrast ratio CR = (L_light+0.05)/(L_dark+0.05) from two colors.

Input Data

Input Color1 R.
Input Color1 G.
Input Color1 B.
Input Color2 R.
Input Color2 G.
Input Color2 B.

Results

21
WCAG contrast ratio.

At a glance:Contrast Ratio Calculator: enter parameters to compute results; complements related calculators.

Formula

CR = (L_light + 0.05) / (L_dark + 0.05).

How to Use

  1. Enter two RGB sets.
  2. It returns contrast (1–21).

Case Studies

White vs Black → CR=21

(1+0.05)/(0+0.05) = 21.

FAQ

Pass thresholds?

Body text AA needs CR≥4.5; large text/UI AA needs ≥3.

Related Tools

References

Content review: Calculatorism Science Team. Formula and numeric tests verified; results for reference only.

Found a problem with the results?

If this calculator's result is wrong, or you have any question about the calculation logic, please let us know. You are viewing:Contrast Ratio Calculator（/color/contrast-ratio）。