A/B Test Calculator
Calculate statistical significance and required sample sizes for A/B tests
Confidence Level:
Control Group (A)
Conversion Rate: 5.00%
Variant Group (B)
Conversion Rate: 5.50%
Not Yet Significant
More data needed to reach 95% confidence level.
Lift
+10.00%
Z-Score
1.585
P-Value
0.1129
95% CI
[-0.12%, 1.12%]
Conversion Rate Comparison
Control (A)5.00%
Variant (B)5.50%
How It Works
Statistical Significance
We use a two-proportion z-test to determine if the difference between control and variant conversion rates is statistically significant. A result is significant when the p-value is below your chosen threshold (1 - confidence level).
Sample Size Calculation
The sample size calculator determines how many visitors you need per variation to detect a minimum effect with 80% statistical power. Larger effects are easier to detect and require smaller sample sizes.