{"id":1501,"date":"2011-04-26T19:30:55","date_gmt":"2011-04-26T14:00:55","guid":{"rendered":"https:\/\/vwo.com\/blog\/?p=1501"},"modified":"2025-04-30T16:18:10","modified_gmt":"2025-04-30T10:48:10","slug":"ab-test-duration-calculator","status":"publish","type":"post","link":"https:\/\/vwo.com\/blog\/ab-test-duration-calculator\/","title":{"rendered":"A\/B Test Duration Calculator [Free Downloadable Excel]"},"content":{"rendered":"\n

In a previous post, I provided a downloadable A\/B testing significance calculator (in excel)<\/a>. In this post, I will provide a free calculator which lets you estimate how many days you should run a test to obtain statistically significant results. But, first, a disclaimer.<\/p>\n\n\n

There is no guarantee of results for an A\/B test.<\/strong><\/b><\/h2>\n\n\n

When someone asks how long should s\/he run an A\/B test<\/a>, the ideal answer would be until eternity or till the time you get results (whichever is sooner). In an A\/B test, you can never say with full confidence that you will get statistically significant results after running the test X number of days. Instead, what you can say is that there is an 80% (or 95%, whatever you choose) probability of getting a statistically significant result (if it indeed exists) after X number of days. But, of course, it may also be the case that there is no difference in the performance of control and variation so no matter how long you wait, you will never get a statistically significant result.<\/p>\n\n\n\n

Download Free: A\/B Testing Guide<\/span><\/a><\/em><\/h2>\n\n\n

So, how long should you run your A\/B test?<\/strong><\/b><\/h2>\n\n\n

Download and use the calculator below to find out how many visitors you need to include in the test. There are 4 pieces of information that you need to enter:<\/p>\n\n\n\n