Free statistical calculators

Sample size for Comparison of proportions

Input
Type I error - Alpha:
Type II error - Beta:

First proportion (%):
Second proportion (%):
Ratio of sample sizes in Group 1 / Group 2:
Result
Number of cases required in group 1:
Number of cases required in group 2:
Total sample size (2 groups together):

MedCalc Software Ltd. Sample size for Comparison of proportions. https://www.medcalc.org/calc/sample-size-comparison-of-proportions.php (Version 23.2.1; accessed March 26, 2025)