Sample Size Calculator
Survey sample size and margin.
🎲Sample Size Calculator
All processing happens locallyWhat this tool does
Sample Size Calculator is a sample size calculator for a target margin of error at a chosen confidence level., every calculation runs inside your browser, so the numbers you enter never reach a server and are never logged.
Results refresh automatically when you change an input; select and copy them anywhere.
How to use it
- Paste or type your content into the input field at the top, or press the sample button to load demo data.
- Adjust the options below the input, such as output format, separators, letter case or precision.
- Press the main button to run the conversion. Results appear instantly in the output panel without a page reload.
- When the result looks right, use the copy button in the corner, or download it as a local file.
Tips and notes
Clean up stray spaces and line breaks before pasting for more accurate results.
FAQ
Use 0.5 for the most conservative estimate since variance peaks there.
Yes, multiply by √[(N−n)/(N−1)] when the population is small.
No — error scales as 1/√n, so you need 4× to halve it.
Yes. The tool is completely free with no usage limits, and you never need an account or a sign-in.
No. All processing runs locally in your browser, so the input never reaches a server and is never logged or stored.
Yes. The layout is mobile-first, so inputs and buttons stay comfortable on phones and tablets in both orientations.
Yes. A copy button in the output panel puts the result on your clipboard, and you can also download it as a text file.