Bayesian AB Test Calculator
Enter visitors and conversions for two variants to get the probability that B beats A, using Beta posteriors with a uniform Beta(1,1) prior.
Operations and HR
5 tools
Which Operations and HR tool do you need?
| Tool | What it answers |
|---|---|
| A/B Test Calculator | An A/B test calculator checks whether the gap between two conversion rates is larger than chance would explain. |
| AB Test Sample Size | An A/B test needs n = (z for confidence + z for power)² × [p1(1−p1) + p2(1−p2)] ÷ (p2 − p1)² visitors per variant. |
| AB Test Significance Calculator | An A/B test is significant when the p-value of a two-proportion z-test falls below 1 minus your confidence level. |
| Bayesian AB Test Calculator | A Bayesian A/B test reports the probability that variant B converts better than A. |
| Split Test Duration | A split test runs until each variant collects the sample size needed to detect your chosen lift. |
All tools
Split Test Duration
Estimate how many days an A/B split test must run from baseline conversion rate, minimum lift, daily traffic, confidence level and statistical power.
AB Test Sample Size
Find how many visitors each A/B test variant needs from baseline conversion rate, minimum detectable effect, confidence and power, with the full working shown.
AB Test Significance Calculator
Compare two conversion rates with a pooled two-proportion z-test. Get the p-value, z-score and relative uplift at 90%, 95% or 99% confidence.
A/B Test Calculator
Compare two conversion rates with a pooled two-proportion z-test: get the p-value, z-score, relative uplift and a verdict at 90%, 95% or 99% confidence.