PRIX TOOLS / Marketing & advertising
A/B Test Sample Size Calculator
Estimate sample size per variant from baseline conversion and relative minimum detectable uplift. The calculation uses 95% confidence and 80% statistical power.
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A/B Test Sample Size Calculator — steps and download
Enter baseline conversion, relative minimum detectable effect, confidence and power. Plan the required sample for each variant.
Is relative MDE the same as a percentage-point difference?
No. A 20% relative uplift from a 5% baseline reaches 6%, a one-percentage-point difference. The calculation assumes two equally sized groups and a normal approximation.
Frequently asked questions
Is the uplift absolute or relative?
Uplift is relative. A 2% baseline and a 10% relative uplift target correspond to a 2.2% conversion rate.
Is relative MDE the same as a percentage-point difference?
No. A 20% relative uplift from a 5% baseline reaches 6%, a one-percentage-point difference. The calculation assumes two equally sized groups and a normal approximation.
Are my files and input data uploaded?
Tool processing runs on your device; file and form contents are not sent to a server for processing. Loading the website still creates standard web requests. Using a contact link is a separate action.
Do I need an account or API key?
No account or API key is required for the tool. Use is free within the file, operation and device limits stated on the page.