A/B Split Test Calculator

Enter the values for your control (A variant) and experiment (B variant) in the form below. Impressions might also be called be views or visitors depending on what you’re testing.

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ImpressionsConversions


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About the A/B Split Test Calculator

This tool was built over a few days when I was annoyed with the slowness of existing ab calculators.

Wanting to make speed as the core feature, I knew using JavaScript in the browser was going I be the best option. Plus it makes the tool feel faster since results are shown right away, instead of waiting on a server to process them.

I want to credit Patrick McKenzie with the algorithm for finding the statistical significance. His open source library ABingo is great for running A/B tests in Ruby on Rails applications and I ported his Ruby implementation to JavaScript for this tool.