Pre-Experiment Power Calculator
Calculate the required sample size, detect the minimum effect size, and estimate how long your experiment needs to run. No account required. Learn more
Experiment Parameters
1%50%
1%50%
Traffic (optional — for runtime estimate)
5%100%
Sample Size per Variant
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Total: --
MDE (absolute)
--
baseline → treatment
Estimated Runtime
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Enter daily traffic above
Power Curve
Sample size required per variant vs. relative effect size. Larger effects are easier to detect.
Adjust parameters above to see the power curve.
AI Planning Advice
Get plain-English interpretation and suggestions for your experiment. Uses Claude AI when available, falls back to built-in templates.
Want to understand the math?
Read our statistics guide on power analysis, MDE, and alpha.