A/B Test Significance Calculator
Check whether two variants differ significantly (two-proportion z-test, 95%).
A/B Test Significance Calculator
Check whether the difference between two variants is statistically significant (95%).
About A/B Test Significance Calculator
The A/B Test Significance Calculator tells you whether the difference between two variants is statistically significant. Enter the visitors and conversions for each variant and it runs a two-proportion z-test, returning each conversion rate, the relative uplift, the z-score, the p-value and a clear significant / not-significant verdict at 95% confidence.
How to use A/B Test Significance Calculator
- Enter visitors and conversions for variant A.
- Enter visitors and conversions for variant B.
- Read the conversion rates, uplift, p-value and whether the result is significant.
Frequently asked questions
What does statistically significant mean here?
It means the observed difference between the two variants is unlikely to be due to random chance. This calculator uses a 95% confidence threshold, i.e. a p-value below 0.05.
What test does it use?
A two-proportion z-test, the standard method for comparing two conversion rates. It reports the z-score and a two-tailed p-value.
Why does it say “collect more data”?
When the p-value is 0.05 or higher, the difference is not yet significant — the sample may be too small or the true difference too small to detect. Gathering more data increases the test’s power.