Power Sample Size Z-Test Calculator

Estimate required sample size for a two-sided z-test from alpha, power, standard deviation, and minimum detectable effect.

Quick Facts

Core Formula
n = ((z_alpha/2 + z_beta) * sigma / delta)^2
Use this as a planning and validation aid, then confirm assumptions for your domain.

Your Results

Calculated
Required n
-
Primary output
z(alpha/2)
-
Secondary output
z(power)
-
Verification metric
Effect Size d
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Interpretation

Ready

Enter values and calculate to get scenario outputs.

How This Calculator Works

This calculator supports rapid scenario analysis and estimation. Start with baseline assumptions, then run sensitivity checks.

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