Tools → Calculators
Compare Two Campaigns
CalculatorsIs one campaign truly better — or is the difference just chance?
Campaign A
Campaign B
Conv. A
10%
Conv. B
13%
Difference
+30%
Confidence
96.5%
The math: a two-proportion z-test, significant at 95% confidence or higher.
Campaign B is genuinely better with 96.5% statistical confidence — the difference is real, not luck. Go with it and shift the budget its way.
The link carries your numbers — anyone opening it sees the same calculation
What does this number mean?
One campaign converts at 10%, another at 13% — the second is better, right? Not necessarily: with a small sample, that gap can come from pure chance. The statistical test (z-test) computes your confidence: above 95%, crown the winner with a clear conscience; below it, keep testing — deciding on a phantom difference costs more than waiting.