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Sample size calculator

Find a minimum survey sample or estimate the margin of error with finite-population correction.

Get started

  1. Use the example values or enter your own measurements.
  2. Calculate, then copy the result or download the available details.

Example

Input

95% confidence, 4% margin, 35% proportion, N = 1,000

Expected result

354 samples

Try it

Good to know

The calculation runs in your browser. Use consistent units in fields with no explicit unit.

Calculation method

The initial size is z²p(1−p)/e². For a finite population, divide that size by 1 + (initial size−1)/N and round up. The error calculation uses the same proportion and finite-population model.

n0=z2p(1−p)e2,n=⌈n01+(n0−1)/N⌉n_0=\frac{z^2p(1-p)}{e^2},\qquad n=\left\lceil\frac{n_0}{1+(n_0-1)/N}\right\rceil

Calculation mode

Find sample size
  • Confidence level · %
  • Margin of error · %
  • Population proportion · %
  • Population size (0 for unlimited)
Find margin of error
  • Confidence level · %
  • Sample size
  • Population proportion · %
  • Population size (0 for unlimited)