ConversionTeam

Ask ten people what a good A/B test win rate is and you'll get ten numbers, none with a definition or a sample size behind them. So we went through ours.

2,288 A/B tests across 71 client engagements, each scored to a win or a loss. A test won if it cleared significance, or if the variation was clearly ahead and the client called it and shipped it. Significance is a guideline, not the only reason to ship.

Three definitions, three numbers:

- ~19% hit statistical significance - the strict bar. Platforms land here too: Optimizely 12%, VWO ~14%, Convert/CXL 20%
- ~50% won outright on the primary metric
- 61% decisive - wins over wins-plus-losses, inconclusive tests set aside

Same tests, three numbers, all real. So next time someone tells you they win 70% of their tests, ask which definition and how many tests. Without both a win rate doesn't tell you much.

Full breakdown's here, broke it out by test type, industry and business model too:

A/B Test Win Rate: What the Data Actually Says What is the average A/B test win rate? Across 2,288 audited tests, ~19% reach statistical significance, ~50% win outright, and the decisive win rate is 61%.