A/B Test Calculator

How many visitors are needed for an A/B test?

Baseline conversion rate:

15% - 25%

20%

Minimum Detectable Effect:

The Minimum Detectable Effect is the smallest effect that will be detected (1-β)% of the time.

Absolute

Relative

Sample size:

1,095

per variation

Statistical power 1-β:

Percent of the time the minimum effect size will be detected, assuming it exists

80%

Significance level α:

Percent of the time a difference will be detected, assuming one does NOT exist