A/B Testing Calculator

Use the Calculator below to figure out the necessary sample size and test duration to ensure your A/B test results aren’t random.

Your current conversion rate can be figured by dividing your last month’s conversions by the total visitors of the last month.

Example: If you made $400 and had 2000 visitors your equation would look like this.

400 ÷ 2000 = .2 or 20%

It’s not important this number be over-thought; take an educated guess.

If you’re a pro and working for a client – you may expect to improve 20%. If you’re starting out maybe 5-15% is more appropriate. Use your best judgement.

What this calculator tells you is two things, for two different confidence levels.

  1. Visitors required for accurate test
  2. Number of Days to run test

Confidence Level is the likelihood that your test results signify true improvement or loss, rather than being a random trend.

80% means 80% chance that the variants performance is ‘true’.

95% means 95% chance that your test results are ‘true’.