Free tool
A/B Test Significance Calculator
Two-proportion z-test with a shippable verdict. Tells you ship A, ship B, or wait N more visitors — instead of dumping a p-value and walking away.
VARIANT A
VISITORS
CONVERSIONS
Rate: 4.50%
VARIANT B
VISITORS
CONVERSIONS
Rate: 6.20%
CONFIDENCE THRESHOLD (%)
VERDICT
Wait. Need approximately 1,752 more visitors per variant before calling this (current p = 0.0912).
LIFT
37.78%
P-VALUE
0.0912
Z-SCORE
1.689
SAMPLE / VARIANT (NEEDED)
2,752
95% CI A: [3.22%, 5.78%] · CI B: [4.71%, 7.69%]
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