Sample Size & Test Duration Calculator

To achieve valid test results*, you need:

A total sample of (users):

Test duration of (days**):

“We were able to test our way from a 5% conversion rate, all the way up to 20%. Without driving any more traffic, our client is getting four times the leads that he was getting before.”

Andrew Miller, Workshop Digital



Copyright 2016 Unbounce

Get Started With Fully Customizable Mobile Responsive Templates

Choose from more than 80 different templates; simply pick one and tweak it as much as you like.
You can also start with a blank page and build everything from scratch. 

Fill out the form and find out how long you need to run your test in order to get valid test results. This will help you avoid false positives and increase the quality of your A/B testing.

A/B Test Duration & Sample Size Calculator

Pro tip! Play around with the calculator and get a better feel for how baseline conversion rate and desired lift affect sample size and test duration. E.g. a conversion rate of e.g. 2% vs. 10%. Or a lift of 5% vs 30%.

*Validity is based on a significance level of 95% and a power level of 80%

** Always round up to full week/weeks to account for seasonality.