Sample Size Calculator for Estimating Population Proportion

Calculate Your Required Sample Size for Population Proportion

If you don't have an estimate, use 0.5 for a conservative (largest) sample size.
Enter as a decimal (e.g., 0.05 for 5%).

Use our free Sample Size Calculator to determine the ideal number of participants required for your study or survey. Ensure statistically significant results when estimating population proportions with a specific confidence level and margin of error. Perfect for researchers, students, and data analysts.

Formula:

Formula for Sample Size (n) to Estimate Population Proportion

The formula used to calculate the sample size for estimating a population proportion is:

n = (Z2 * p * (1-p)) / E2

Where:

  • n = Required Sample Size
  • Z = Z-score corresponding to the desired Confidence Level (e.g., 1.96 for 95% Confidence)
  • p = Expected Population Proportion (as a decimal, e.g., 0.5 for 50%). Use 0.5 if unknown for maximum sample size.
  • E = Margin of Error (as a decimal, e.g., 0.05 for ±5%)

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