Survey Sample Size Calculator
Estimate survey respondents needed for a chosen margin of error.
Quick answer: enter your details below and click Estimate Survey Sample — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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How to use
- Enter the population size.
- Enter the margin of error you can accept.
- Pick a confidence level and click Estimate Survey Sample.
About this tool
Enter population size, desired margin of error, and confidence level, and the tool estimates the sample size using the standard Cochran formula with a 50% proportion. This is a planning estimate; real surveys also need to consider response rates and sampling method.
Frequently asked questions
Does a bigger population need a much bigger sample?
Not much. Beyond a few thousand, population size barely changes the required sample.
What about people who do not reply?
Invite more than the target. If only half reply, you need to invite roughly twice the sample size.