A/B Test Significance Calculator

Two-sample proportion z-test for your A/B test: p-value, confidence interval, and a practical-significance flag that says whether the difference is worth acting on.

Control conversions

Control visitors

Variant conversions

Variant visitors

Significance level α

Minimum practically meaningful lift (percentage points)

Calculating…

The z-distribution under H₀. Orange tails are the rejection regions at your α; the marker is your observed z.

Assumption check

Compares conversion rates (or any yes/no outcome) between a control and a variant. Pooled standard error, two-sided test.

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