Math

Free Sample Size Calculator

Minimum sample size needed for a survey.

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Inputs

%
%

Result

Required sample size

383

Unadjusted (infinite population)385

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Short answer

Minimum sample size needed for a survey.

What is the Sample Size Calculator?

Minimum sample size needed for a survey.

How does the Sample Size Calculator work?

Enter the inputs above and read the result.

Formula

n₀ = z²p(1−p) ÷ e²; n = n₀ ÷ (1 + (n₀−1)/N)

Variables

  • eMargin of error
  • NPopulation size

Explanation

The finite population correction reduces the needed sample size when the population itself is small.

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            Related concepts

            The Sample Size Calculator sits inside the Math Calculators hub, in the statistics & probability cluster. Describing data and quantifying uncertainty. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.

            distributiondispersionsignificancesamplepopulationexpected value

            Practical use cases and industry applications

            Understanding Sample Size

            Minimum sample size needed for a survey. Within math calculators, sample size belongs to the statistics & probability cluster, where it shares terminology and assumptions with closely related tools.

            Learning how sample size is calculated

            The finite population correction reduces the needed sample size when the population itself is small. Working through the variables one at a time — e, N — makes the result reproducible by hand and easier to sanity-check.

            Using sample size to make a decision

            Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.

            How sample size compares with related measures

            distribution, dispersion, significance, sample all describe adjacent aspects of statistics & probability. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.

            Frequently asked questions

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