Topic

Sample size and power

How to calculate sample size and statistical power for surveys, experiments and regression models, with free calculators.

How to Calculate Sample Size: Surveys, Experiments and Power Analysis

Work out how many participants you need, whether you are estimating a percentage in a survey or testing a hypothesis, with formulas, quick-reference tables and free calculators.

October 13, 20264 min read

Free Sample size and power tools

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A/B Test Significance CalculatorFree A/B test calculator: compare conversion rates with a two-proportion z-test, relative uplift, confidence interval and probability B beats A.Power Analysis and Sample Size CalculatorFree a priori power analysis for t-tests, ANOVA, correlation, proportions, chi-square and regression. Required sample size and power curve, like G*Power.Survey Sample Size CalculatorFree survey sample size calculator: responses needed for your margin of error and confidence level, with finite population correction and response rate.