Sample Size Calculator for Clinical Trials

Input Parameters

Study Design

Two Proportions Two Means

Test Type

Two-sided One-sided

Significance Level (α)

Power (1−β)

Allocation Ratio (n₂/n₁)

Proportion in Control Group (p₁) e.g., 0.30 for 30%

Proportion in Treatment Group (p₂) e.g., 0.20 for 20%

Results

Sample Size Per Group

n₂

Total Sample Size

Reference: Chow, S.C., Shao, J. & Wang, H. (2017). Sample Size Calculations in Clinical Research, 3rd ed.
Results should match PASS, G*Power, or nQuery for the same parameters.

Disclaimer: This tool is for educational and research planning purposes. Always consult a biostatistician for clinical trial design.