Math Calculators

Sample Size Calculator

Find the sample size a survey needs for a chosen confidence level and margin of error.

%
%
Required sample size
—

How to use the Sample Size Calculator

  1. Fill in each field with your own figures — the defaults are only there as an example.
  2. The result updates as you type, so there is no button to press.
  3. Check the breakdown under the main result for the supporting numbers.
  4. Use the copy button to take the result with you, or share the link to reload the same inputs.

Sample Size Calculator — frequently asked questions

Is this sample size calculator free to use?

Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.

How accurate is the result?

The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.

Can I use it on my phone?

Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.

Related reading

What people search for

This page answers each of these searches. They are the exact phrases visitors use to find the sample size calculator.

  • sample size calculator
  • how many respondents
  • margin of error
  • statistically significant sample
  • survey sample size
  • sample size

About this calculator

Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.

Last reviewed August 13, 2026 · Calculation runs client-side · No data collected · Report an error