Plan the test. Trust the result. Keep what you learned.
Free calculators for the three questions every experiment raises. Each one gives you a readout you can paste straight into Slack or a doc.
Sample size & duration
Visitors per variant, run time in whole weeks, and the smallest lift your traffic can detect.
Plan a test → Did the variant actually win?Significance
Lift with a confidence interval, the p-value and a built-in split check, written up in plain English.
Read a result → Can we trust these numbers?Sample ratio mismatch
Check whether traffic split the way you intended, and see the usual causes when it didn't.
Check the split →The weekly product roundtable, with the numbers in the room.
Post updates on tests and projects, review results together, talk through why, and decide what's next. Every test and discussion stays searchable. Founding teams get 50% off for a year.
Want a second set of eyes on your program?
Jacob Voytovich co-led 400+ A/B tests a year at Priceline. His funnel and experimentation audit finds where people drop off, ranks the fixes and writes your first experiments. From $2,000.