Tool · 1 min
A/B test sample size calculator: How long should my test run?
Free A/B test sample size calculator: enter baseline rate, MDE, significance and power to get visitors per variant and duration. Method and assumptions shown.
Tool
Free CRO tools: Quick answers, maths included
Small calculators for the questions that come up every week. Each one shows exactly how it works, so you can trust the number.
Experiment science
Program strategy
Tool · 1 min
Test idea ranker: Which A/B test should you run first?
Score test ideas with the PXL framework (by CXL): ten evidence-based criteria, a ranked backlog and CSV export. Free, runs in your browser, nothing is uploaded.