Sample Size Calculator
Math ToolsHow many survey responses do you need?
Embed this tool on your websiteFree
- Choose how tall the frame should be.
- Press Copy code.
- Paste it into your page, blog, WordPress or Notion HTML block.
The tool runs inside your visitor's browser, nothing is uploaded, and a small "Powered by ToolCloak" line stays under it. The second line (script) is optional: it makes the frame fit the tool's height.
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History
All history →Sample Size Calculator — at a glance
Plan a survey with the right number of respondents.
How to use it — step by step
Confidence level, margin of error and, if known, the population size.
Enter your numbers
Fill in the fields — sensible example values are already filled in.
Pick your options
Choose any dropdowns or switches that apply to your case.
Calculate Sample Size
Press the button. The result is created instantly on your device.
Read the answer
The main answer is shown big at the top, with details below it.
Pro tips
Small things that make the result better.
Quick facts
Frequently Asked Questions
What is margin of error?+
How far the survey result may differ from the true value, in either direction.
Why 50% by default?+
It is the worst case and gives the largest sample size, so it is safe.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.