A/B test significance calculator
Enter visitors and conversions for versions A and B to see whether the difference is significant.
Fill in all four fields to test your result.
Everything is worked out in your browser, and nothing you type is sent anywhere.
What the result means
The p-value is the chance of seeing a gap this large or larger if A and B really performed the same.
The formula
z = (rate B − rate A) ÷ standard error
p-value = 2 × (1 − Φ(|z|))
A worked example
Version A gets 10,000 visitors and 300 conversions, 3.00%. Version B gets 10,000 and 360, 3.60%: 20.00% higher. A p-value of 0.018 makes that significant.
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