Sample Size Calculator
Determine the survey sample size needed for a given confidence level and margin of error.
Inputs explained
- Population Size — The total size of the group you are studying. Example: 10000.
- Confidence Level — How confident you want to be — 90%, 95%, or 99%.
- Margin of Error (%) — The acceptable error range. 5% is common. Enter 5 for ±5%.
How to use it
- Fill in the fields above — each input has a hint describing exactly what to enter
- Press Calculate to get your result instantly, right on this page
- Copy the result, save the tool to favorites, or share and embed it anywhere
Understanding the result
Example: For 10,000 people at 95% confidence and ±5% error, you need about 370 responses.
Frequently asked questions
Is the Sample Size Calculator free to use? Yes — it is completely free, with no sign-up, no download and no usage limits. You can use it as often as you need.
Is my data private? Yes. The calculation runs entirely in your browser — the values you enter are never sent to our servers, stored or shared with anyone.
What information do I need? Just the following: Population Size, Confidence Level, Margin of Error (%). Each field includes a hint explaining exactly what to enter.
Can I use it on my phone? Yes — the tool is fully responsive and works on any device, and the same calculator is available in the EasyWorkCalcs mobile app.
Privacy
Everything you enter into the Sample Size Calculator is processed entirely in your browser. Nothing is uploaded, stored or shared — your data stays on your device.