How does this calculator work?

Enter the requested values, select the appropriate options, then calculate. The result is an estimate based on the formula used by this calculator.

Are calculator results guaranteed to be exact?

Results are estimates based on the inputs and formula used by the calculator. Review the assumptions and use professional advice where appropriate.

ONLINE CALCULATOR

Sample Size Calculator

PopulationMargin of error (%)Confidence (%)

ResultCalculated for the selected inputs

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What Is the Sample Size Calculator?

Sample Size Calculator is used to estimate the number of observations needed for a statistical study from the selected confidence, error, and population assumptions. Use it to check a calculation, study the underlying concept, or test different values without doing the arithmetic by hand.

How to Use the Sample Size Calculator

Enter the values requested by the calculator.
Check the units and assumptions for each field.
Select Calculate to generate the result.
Change an input and calculate again if you want to compare scenarios.

Calculation Method

The calculator applies the mathematical relationship associated with Sample Size Calculator to the values entered and returns the corresponding result.

Example

Example: enter the values relevant to your Sample Size Calculator scenario, calculate the result, and then change one input at a time to see how that specific variable affects the outcome.

Understanding the Result

The result is determined by the inputs required for Sample Size Calculator, the units used, and the assumptions built into its calculation. Review each field before comparing results.

Tips and Notes

For a useful comparison, keep units consistent and test more than one realistic scenario. When the result affects an important financial, health, legal, or technical decision, verify key assumptions with an appropriate authoritative source.