Sample Size Calculator for Proportions
Determine the sample size needed for a proportion with desired precision
Use 0.5 if unknown (most conservative)
0.05 = +/- 5 percentage points
Results:
Required Sample Size: 385
Conservative Estimate (p=0.5): 385
Z-Score Used: 1.960
Adjusted for Design Effect:
DEFF = 1: n = 385
DEFF = 1.5: n = 578
DEFF = 2: n = 770
DEFF = 2.5: n = 963
About Sample Size for Proportions
Formula: n = z² × p(1-p) / e²
FPC: n_adj = n / (1 + (n-1)/N) for finite populations
Design Effect: Multiply n by DEFF for complex sampling designs.