Free Tools
Free tools for
marketers and analysts
Calculators, models, and utilities built by Jarrah's analytics team and made free for everyone. From A/B test sizing to predictive LTV, media mix modelling, and data infrastructure — tools that cover the full stack of modern marketing analytics.
Statistical Significance Calculator
Enter your control and variant conversion data to find out if your A/B test results are real — not luck. Get instant p-values, confidence intervals, and relative uplift.
- p-value (two-proportion z-test)
- Confidence interval on the difference
- Relative uplift %
- Pass/fail verdict at 90%, 95%, or 99% confidence
A/B Test Power Calculator
Calculate how many visitors you need per variant before you start testing. Set your baseline rate, minimum detectable effect, and confidence level — get sample size and estimated runtime.
- Required visitors per variant
- Total visitors needed
- Estimated test runtime (if daily traffic provided)
- Supports relative and absolute MDE
Work with Jarrah
Need more than a tool?
These tools are built from the work we do every day for clients. If you need the full analytical program — attribution, experimentation, media mix, or predictive modelling — that's what we do.
See our CRO work →