GenGrowth

A/B Test Sample Size Calculator

Calculate the required sample size for statistically significant A/B test results.

Results

Sample Size Per Variation

8,161

Total Sample Size

16,322

How to Use This Calculator

  1. Enter your current conversion rate as the baseline
  2. Set the minimum improvement you want to detect
  3. Choose your statistical confidence level and review the results

FAQ

What is a good sample size for an A/B test?

It depends on your baseline conversion rate and the effect you want to detect. Use this calculator with your actual numbers for an accurate estimate.

What is Minimum Detectable Effect?

MDE is the smallest relative improvement in conversion rate that your test can reliably detect. A 20% MDE means you want to detect at least a 20% relative lift.

How long should I run my A/B test?

Divide the total sample size by your daily traffic. Most tests need 2-4 weeks for reliable results.