basic

Statistical Power & Type II Error Calculator

Power = 1 − β — probability of detecting a true effect.

Calculates the statistical power of a one-sample z-test from effect size, sample size, and significance level.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

z_β = |μ1−μ0|×√n/σ − z_α; Power = Φ(z_β)

In depth

Calculates the statistical power of a one-sample z-test from effect size, sample size, and significance level.