🧪 AB Test Calculator
Enter your control and variant visitor and conversion counts to see the lift, z-score, p-value, and whether the difference is statistically significant.
What this calculator does
An A/B test compares two versions of something — a webpage, an email, an app feature — by measuring the conversion rate of a control group against a variant group. This calculator finds each group’s conversion rate, the lift between them, and whether the difference is statistically significant.
How the calculation works
The calculator computes each group’s conversion rate (conversions divided by visitors), then runs a two-proportion z-test: it pools both groups’ conversion rates to estimate a standard error, and divides the difference in rates by that standard error to get a z-score. The z-score is converted into a two-tailed p-value using the standard normal distribution. A common threshold for statistical significance is a z-score of 1.96 or higher (roughly a p-value below 0.05), corresponding to 95% confidence.
Larger sample sizes make small differences easier to detect reliably. This tool is for general business and educational planning purposes and does not replace a full experimentation platform’s statistical engine.