📊Sample Size Calculator
Find the survey sample size you need.
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About this calculator
Free Sample Size Calculator — find the sample size needed for a survey from margin of error, confidence level and population.
How to use
Enter your Margin of Error, Population Size, Confidence Level above — the result updates instantly as you type or drag the sliders. It's free and needs no sign-up.
Frequently Asked Questions
What does the Sample Size Calculator do? ▼
Find the survey sample size you need.
How does the Sample Size Calculator work out the answer? ▼
The Sample Size Calculator applies the standard mathematical formula for this problem to the values you enter and returns the exact result instantly.
How do I use the Sample Size Calculator? ▼
Enter your values using the input fields or sliders. The result updates instantly — no submit button needed. All calculations run in your browser.
Can I use the Sample Size Calculator for homework or study? ▼
Absolutely. The Sample Size Calculator is a great way to check your work and understand the steps. Try solving the problem yourself first, then compare with the calculator.
Is the Sample Size Calculator free? ▼
Yes — completely free. No sign-up, no download, and no account required. Works in any browser.