Calculator

A/B Test Sample Size Estimator

Conversion Uplift: The percentage improvement you want to detect. Smaller uplifts (like 5-10%) need longer to validate than larger changes (20%+)
Baseline Rate: Your current conversion rate - lower rates need longer tests
Confidence Level: Higher confidence needs longer tests but reduces false positives
Monthly Traffic: More traffic = faster tests
Variants: More variants split your traffic, needing longer tests

The following graph is showing you how long you should run an A/B test.
Very useful to know if you should start A/B testing or not