Sample size before you launch, significance after — free stats calculators that keep your experiments honest.
Two-proportion z-test for conversion experiments — p-value, confidence, relative lift and whether it's significant.
Required visitors per variant to detect a target lift at your power and significance — before you launch.
Wald and Wilson confidence intervals for a proportion — the honest error bars around your conversion rate.
Update a prior probability with new evidence — the engine of rational belief, spam filters and medical reasoning.
Convert a value to a z-score and percentile, or find probabilities under the bell curve — for any mean and SD.
How simulation accuracy improves with sample count — standard error, and samples needed for a target precision.
Every tool on ToolJolt is free, runs in your browser and needs no sign-up.