Statistics
Sample Size Calculator
Calculate the required sample size for statistical studies
Required Sample Size385 respondentsView results
%
Real-time Results
Required Sample Size
385respondents
Infinite Population n₀
385
Before finite population correction
Z-Score Used
1.960
Supported inputs
| Input | Description |
|---|---|
| Confidence Level | Higher confidence levels require larger sample sizes 80% · 85% · 90% · 95% · 99% |
| Margin of Error (%) | Lower margins of error require larger sample sizes |
| Population Size | For large populations (>20,000), the impact on sample size is minimal |
| Expected Proportion (p) | Expected success proportion (use 0.5 for max conservatism) |
Formula
n₀ = z² × p × (1−p) / e² n (finite) = n₀ / (1 + (n₀−1) / N) z = 1.96 for 95% | 2.576 for 99% Use p = 0.5 for the most conservative (largest) sample size
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