StatPowers
Confidence Level (e.g. 0.95)

Mean Sample Size Calculator

Target Margin of Error
Standard Deviation Estimate
Required Sample Size (n) =

Proportion Sample Size Calculator

Target Margin of Error
Proportion Estimate (p̂, optional)
Required Sample Size (n) =

Mean Sample Size / Power Calculator

Significance level
Test Type
Absolute Effect Size
Standard Deviation Estimate