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Free A/B Test Calculator Based On Opportunity Costs


I have recently published a post at ConversionXL that challenges the conventional wisdom in the Conversion Rate Optimization industry: that you should wait until you have achieved 95% significance before ending an A/B test. My argument is that the right time to end an A/B test is when the Opportunity Costs from not ending the experiment start becoming larger than the Error Costs you run from ending it. This bases the decision on ROI, not an arbitrary rule.

Read the whole thing for the fuller argument, and an explanation of how we make the calculation.

If you would like to download our Calculator, please sign up for our newsletter above. You will see a download link on the thank you page.

If you have any feedback on this calculator, please write me at will [at] If possible, I will make improvements to this calculator based on your experience with it.

If you’re looking for ways to improve your conversion rate, consider an explainer video from us.

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