➗ Proportion Sample Size Calculator
Estimate sample size for a proportion at 95% confidence.
Result
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How this calculator works
Estimate sample size for a proportion at 95% confidence.
Formula
n=z²p(1-p)/e²
Example
At 50% proportion and 5% margin, n≈385.
Frequently asked questions
What does the Proportion Sample Size Calculator do?
Estimate sample size for a proportion at 95% confidence.
Are the results exact?
The calculator follows the displayed formula. Rounded display values may differ slightly from full-precision results.
Can I use negative or decimal values?
Most fields accept decimals and negative values when they make sense for the formula.
How should I check an important result?
Review the formula, verify your entries, and confirm high-stakes work with a qualified teacher or professional.