This calculator will help you to determine the number of survey replies needed to achieve a properly representative sample of your target population.

Calculations used

Sample Size = (Z-score)2 × StdDev × (1 − StdDev) / (margin of error)2
True Sample = (Sample Size × Population) / (Sample Size + Population − 1)

Where:
90% − Z-Score = 1.645
95% − Z-Score = 1.96
99% − Z-Score = 2.576
StdDev = 0.5