Raosoft Sample Size Calculator

n = (Z² × p × (1-p)) / e²

Z = Z-score • p = Response distribution • e = Margin of error • N = Population (for adjustment)

Population Size (N) (Total people/items)

Margin of Error (%) (Default: 5%)

Confidence Level (Default: 95%)

Response Distribution (%) (Default: 50% - most conservative)

Recommended Sample Size

0% of total population

Population (N)

Confidence

95%

Margin of Error

Z-Score

1.96

Step 1: Get Z-score from confidence level Z = 1.960 (for 95%)

Step 2: Convert margin and distribution to decimals e = 0.05, p = 0.50

Step 3: Calculate initial sample size (infinite population) n₀ = (Z² × p × (1-p)) / e² = (1.96² × 0.5 × 0.5) / 0.05² = 384.16

Step 4: Apply finite population correction n = n₀ / (1 + ((n₀-1) / N))

Final Sample Size (rounded up): n ≈ 377