Statistics & Probability
Sample Size Calculator
Lets users solve and check sample size instantly with formula, steps and examples — no manual math.
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120
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199
Your result
Required sample size
385
Required sample size ≈ 385 respondents.
About this calculator
Sample size for a proportion: n = z²·p(1−p)/e², with a finite-population correction when the population is specified. Worst case p = 50% maximizes the required size.
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