A/B Pre-test Calculator by Speero

Speero's A/B Pre-test Calculator helps you answer all important pre-test questions like:

— What is the minimal detectible effect I can test for?
— How long should I test for considering the effect?
— What's the sample size?

— How to use Speero's A/B Pre-test Calculator? —

Type in the number of weekly sessions or users, conversions, and a number of test variants, and see if your website has the capacity to test your ideas.

Or just sign in with Google Analytics and let Speero’s calculator get the results for you.

Speero’s A/B Pre-test Calculator is pre-defined for 2 variants (including control), confidence of 95% and statical power of 80%.

— Why Speero’s A/B Pre-test Calculator? —

One of the best A/B Pre-test Calculators, now in Plugin mode.

Determine sample size, MDE, and test duration on the go.

Filter By Page Path and compare pre-test data from multiple URLs.

The best part is that Speero’s A/B Pre-test Calculator connects with your GA4, letting you answer all your pre-test questions without leaving the tab.