Know if your test actually won.
Free Bayesian A/B test calculators for marketers. Paste your numbers, get a plain-English verdict — no p-values, no statistics degree required.
Ship B. Expected uplift +24.8%.
Two calculators. Both free.
Bayesian results calculator
Paste visitors and conversions for A and B. Get probability, expected uplift, credible intervals, and a plain-English recommendation.
Sample size calculator
Work out how many visitors and how long you need before starting a test — so you don't call a winner too early.
More tools, soon
Frequentist significance, revenue impact, sample ratio mismatch, sequential testing — all coming to the same clean toolkit.
Answers you can act on.
Bayesian testing gives you a direct answer to the question you actually have: what's the chance B is better than A, and by how much?
No p-values
Get a probability, not a significance test. Easier to explain, harder to misinterpret.
Peek any time
Bayesian methods don't fall apart if you check the results before the test ends.
Real recommendations
Ship, keep testing, or roll back — with the reasoning in plain English underneath.
Plain-English guides.
The learning centre is coming soon — deep, opinionated guides on running experiments that actually improve performance.
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