# Sample size calculator

Eppo's Sample Size Calculator operates on top of your data to determine how many subjects you need to detect the effect of interest. Use the Sample Size Calculator to plan how long to run an experiment for and to understand how experiment setup and analysis settings affect what effect sizes you can reliably measure.

## Quickstart

- From the
**Definitions**page, create a new**Entry Point SQL**(learn more). - Visit the
**Sample Size Calculator**from the**Experiments**page, and create a new calculation. - Select
**Entity**,**Entry Point**, and**Metrics**, then**Run**the calculation. - Once the calculation completes, adjust experiment and analysis plan settings as needed.
- Get sample size and Minimum Detectable Effects at different experiment durations.