Compare Two Proportions Calculator
Use this calculator to compare two proportions (percentages) from independent samples. It performs a two-proportion Chi-Squared test and provides the p-value, confidence interval, odds ratio, and relative risk.
Example: Compare 45% (n=120) vs 60% (n=150).
Computational notes
MedCalc uses the "N-1" Chi-squared test as recommended by Campbell (2007) and Richardson (2011).
The confidence interval is calculated according to the recommended method given by Altman et al. (2000).
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Literature
- Altman DG, Machin D, Bryant TN, Gardner MJ (Eds) (2000) Statistics with confidence, 2nd ed. BMJ Books. (p. 49)
- Campbell I (2007) Chi-squared and Fisher-Irwin tests of two-by-two tables with small sample recommendations. Statistics in Medicine 26:3661-3675.
- Richardson JTE (2011) The analysis of 2 x 2 contingency tables - Yet again. Statistics in Medicine 30:890.
How to cite this page
- MedCalc Software Ltd. Compare Two Proportions Calculator (Chi-Squared test) | MedCalc. https://www.medcalc.org/en/calc/comparison_of_proportions.php (Version 23.6.1; accessed June 23, 2026)
Other free statistical calculators
- Test for one proportion
- McNemar test on paired proportions
- Fisher's exact test for 2x2 table
- Two-way Chi-squared test
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- Post-hoc power analysis