basic

Sample Size for Proportion Study Calculator

n = z²·p(1−p)/E² — minimum sample size for a proportion.

Calculates the minimum sample size needed to estimate a proportion with a specified margin of error and confidence level.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
Was this helpful?

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

n = (z × α/2)² × p × (1−p) / E²; z95=1.96, z99=2.576

In depth

Calculates the minimum sample size needed to estimate a proportion with a specified margin of error and confidence level.