Sample Size Calculator
Free online sample size calculator. Required sample size for significance. Visualize data easily.
Sample Size Calculator
Confidence Level
90%
95%
99%
Margin of Error
Population Proportion (default 0.5)
Population Size (optional)
Required Sample Size
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385
n₀ = (1.9600² × 0.5 × 0.5) / 0.05²
Z-Score (95%)
1.9600
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Unadjusted (n₀)
385
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Interpretation
We need
385
respondents for 95% confidence ±5%