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Sample Size Calculator
Estimate a simple large-population sample size from confidence, margin of error, and expected proportion.
Estimated responses
385Normal-approximation planning estimate for a large population and simple random sample. Real studies may need design effects, response-rate planning, or expert review.
About this tool
How it works
Uses the normal approximation n = z²p(1−p)/e² and rounds up; it does not apply finite-population correction.
A practical way to use it
Estimate the responses needed for a 95% confidence level and ±5 percentage-point margin.
Use results as a practical aid, and verify important decisions against your own source data and qualified guidance.