How this calculator works
The normal-approximation formula is n=z*²p(1−p)/E², and the result is rounded upward.
Formula
n=z*²p(1−p)/E²Estimates sample size for a proportion using a normal approximation and no finite-population correction.
Worked example
95% with 5% margin is a verified test case used by the calculation engine.
Assumptions and limitations
- The calculation estimates sample size for a proportion.
- No finite-population correction or design effect is applied.
- Use p=0.5 when a conservative maximum-variance assumption is appropriate.
Methodology & sources
This calculator uses deterministic, versioned calculation logic. The formula and verified examples above are part of the calculation definition used by CalcuMint. Technical calculation version: 1.
- CalcuMint deterministic statistics engine
Frequently asked questions
Why is the sample size rounded up?
A fractional participant cannot satisfy the target, so the calculated requirement is rounded upward.
Does this account for a finite population?
No. This version does not apply finite-population correction.