Sample size
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Required sample385
Worked example
Given: Confidence level = 95%; Margin of error = 5 %; Expected proportion = 50 %
Result: Required sample = 385
How it is calculated
1. Enter the values you know. 2. The calculator converts them to base units and applies the formula. 3. The result is shown in the unit you choose.
Frequently asked questions
How do I calculate it?
Given: Confidence level = 95%; Margin of error = 5 %; Expected proportion = 50 %. Result: Required sample = 385.
Is the calculator free and private?
Yes. It is free, needs no sign-up and runs in your browser — the numbers you type stay on your device.