AB Math Sucks is an A/B test duration calculator that tells you the truth: most tests need to run way longer than you think, and you’re probably going to call it early anyway.

Toggle between “Aggressive” mode (reality checks with dark humor) and “Nice” mode (gentle but honest guidance). Either way, you get accurate statistical calculations for how long your test needs to run to detect the effect size you care about at the confidence level you need.

Built for growth teams who are tired of pretending statistical significance works the way their executive dashboard wants it to work.