Statistical Significance Calculator
Are your A/B test results real or just noise? Enter your control and variant data to get a p-value and confidence level using a two-proportion z-test.
Enter the visitor and conversion counts for each variant from your testing platform.
Control (A)
Variant (B)
Results will appear here after you click Calculate.
Understanding statistical significance
Statistical significance tells you the probability that the difference between your control and variant happened by chance. A p-value below 0.05 means there's less than a 5% chance the difference is random — it's likely real.
Key concepts
The probability of observing your results (or more extreme) if there's actually no difference between A and B. Lower p-value = stronger evidence of a real effect.
How many standard deviations your observed difference is from zero. A z-score above 1.96 (or below -1.96) is significant at the 95% level for two-tailed tests.
Two-tailed tests check if B is different from A (either direction). One-tailed tests only check if B is better. Use two-tailed unless you have a strong directional hypothesis.
Need help interpreting your test results?
Statistical significance is just the starting point. Our CRO team will tell you whether to ship, iterate, or pivot — and what to test next.