Free A/B Test Calculator
Calculate statistical significance of your A/B tests. Enter visitors and conversions for each variant to see if your results are reliable at 95% confidence. No signup required.
100% free — no account needed
Variant A (Control)
Variant B (Test)
Free A/B Test Calculator Features
Know if your A/B test results are statistically significant
P-Value
See the exact p-value and whether it's below the 0.05 threshold.
Sample Size
Get minimum sample size recommendations for reliable results.
Statistical Significance
95% confidence level testing using a two-proportion z-test.
Relative Uplift
Calculate the percentage improvement of variant B over variant A.
FAQ
What is statistical significance?
It means the difference between variants is unlikely due to random chance. At 95% confidence, there's only a 5% probability the result is random.
How many visitors do I need?
It depends on the expected difference. Typically 1,000-10,000 visitors per variant for a 10-20% conversion rate difference. The calculator recommends a minimum.
What if my result isn't significant?
Either run the test longer to collect more data, or the difference between variants is too small to detect reliably. Don't make decisions on non-significant results.
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