Tool 501 · Advanced statistics planner
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.
PrivateRuns locally in your browser.
TransparentFormula and assumptions shown.
Power-awareA/B planning with α and power.
Research-readyDEFF, FPC and non-response.
Plan a survey sample
Estimate a percentage or prevalence with a target confidence and precision.
Unknown? 50% is conservative and gives the largest usual requirement.
Use only for a fixed finite population sampled without replacement.
Use historical data or a pilot-study estimate.
50% is most sample-efficient for two arms.
Advanced survey planning
1.0 = simple random sampling; >1 inflates variance for complex designs.
Used to translate completed responses into invitations/recruits.