Use the Sample Size Calculator

Overview

The Sample Size Calculator gives real-time visibility into how your experiment is progressing toward statistical relevance, helping answer:

  • Is my experiment collecting enough data?

  • How long until I can trust the results?

  • Is the test ready to conclude?

This removes the guesswork, ensuring your results are based on sufficient traffic and conversions before you act on them.

Note

This feature is based on the methodology used in our public A/B Test Sample Size Calculator, automated so you don't need to manually input your data or recalculate it as the experiment progresses.

The three stages

1. Collecting Data

The initial phase. The calculator stays in this mode until every variation reaches:

  • At least 500 users.

  • At least 10 conversions on the main goal (usually Sale).

2. Running Test

Once the minimum thresholds are met, the calculator starts projecting how many more days are needed for your experiment to reach maturity. This projection updates continuously as new data comes in.

3. Results ready

Your experiment has gathered enough data to be statistically relevant. You can now confidently review the results and make a decision.

At this stage, you'll see one of two outcome messages:

  • The experiment was a success - Chance to Win was high enough.

  • The experiment came close to succeeding - consider making adjustments and running it again.

When the calculator can't run

If your experiment is Paused, Expired, or has 0% traffic allocated to Control, the calculator shows a message explaining that sample size can't be calculated until the experiment is updated.

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