A/B Test Statistical Calculator

Pre-test calculator

Use this before you run the experiment. It’ll show you the sample size needed for the experiment, how long you need to run it for, and what the minimum detectable effect is.

Post-test calculator

Use this during or after the experiment. It’ll show you whether you have a statistically significant result, and will help you analyse performance.

Insert your test data

P-value
Z-score
Changing to two-sided experiment might change the outcome of the test

Test Results

Insights

 
Control
Variant
Visitors
Conversions
Conversion rate
Uplift
-
not significant
Significance level
-
 
Visitors
Conversions
Conversion rate
Uplift
Significance level
Control
-
-
Variant
not significant

Next Steps

Have you reached your sample size?  

We need to know if you reached your sample size to decide on the outcome of the test and recommend next steps.

Yes No Don't know

Outcome

You’ve got a significant result! Your variant performs better than control.

Next steps

Conclude your experiment and analyse the results.

Outcome

If you haven’t reach your sample size, the observed uplift should not be analysed yet, even if it reached the desired confidence level.

Next steps

Continue to run your experiment until you’ve reached your sample size. We estimate this would take another 12 days based on the data you provided.

Next steps

We recommend using our Pre-test calculator to find out what your sample size should be.

We estimate it would take another 12 days to get a conclusive result based on the data you provided.