Sample Size Calculator

Determine the required sample size for surveys and statistical studies.

Survey Parameters

How confident you want to be that the results are accurate

%

The acceptable range of error (typically 3-5%)

Total population size (leave empty if unknown or very large)

%

Expected % of sample with the attribute (use 50% if unknown)

About Sample Size

Sample size determines how many responses you need for statistically valid survey results.

Key Factors:

  • Higher confidence = larger sample needed
  • Smaller margin of error = larger sample needed
  • Finite population reduces sample size needed

Related Calculators

Sample Size Result
n = (Z² × p × (1-p)) / E²
Required Sample Size385