OneFreePlace
FREE ONLINE TOOL

Free Sample Size
Calculator

Advanced browser-based sample size planner for surveys, means and A/B experiments, with finite-population correction, design effects, response adjustment, power analysis and reverse margin-of-error checks.

Open this tool in its own window ↗

FreeUse this tool without paying.No sign upStart with the tool right away.Clear stepsRead the tool’s own guidance.

About Free Sample Size Calculator

From a quick survey estimate to an A/B experiment power plan. See not only the answer, but the assumptions, recruitment target, finite-population impact, sensitivity and method behind it.

Workspace options

  • Confidence level (%)
  • Margin of error (± percentage points)
  • Expected proportion (%)
  • Population size (optional)
  • Design effect (DEFF)
  • Expected response / retention (%)

Available actions

  • ☼ / ◐
  • Survey proportion
  • Estimate a mean
  • A/B experiment
  • Reverse margin of error
  • Quick poll