Proportion Sample Size Calculator
Plan a simple-random proportion sample from confidence, margin, and an explicit anticipated proportion.
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How to use Proportion Sample Size Calculator
Initial n=z²×p(1−p)/E². An optional finite population applies n/(1+(n−1)/N), then the required count rounds upward.
- Enter margin fraction e, anticipated proportion p, finite population (0 = unbounded), confidence fraction (0.5–0.999).
- Check the model, units, and supported limits before calculating.
- Run the tool, inspect the result, then copy or download it.
Good to know
- Margin fraction 0<E<1, anticipated proportion 0<p<1, population 0 for unbounded or a whole number ≥2. Planning approximation only: no design effects or nonresponse allowance.
- Runs locally. Numeric inputs are bounded; floating-point output is approximate and rounded to 12 significant digits. Unsupported or non-finite calculations produce an error.
Common questions
How does Proportion Sample Size Calculator calculate its result?
Initial n=z²×p(1−p)/E². An optional finite population applies n/(1+(n−1)/N), then the required count rounds upward.
What assumptions and boundaries apply?
Margin fraction 0<E<1, anticipated proportion 0<p<1, population 0 for unbounded or a whole number ≥2. Planning approximation only: no design effects or nonresponse allowance.
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