StatSageSample size calculator

How many participants do you need?

Choose your planned test and expected effect size. StatSage computes the sample size needed to detect it — before you collect a single data point. Free, no account needed.

What are you planning to do?

Expected effect size (Cohen's d)

Unsure? “Medium” is the conventional planning default; a pilot study or prior literature gives a better estimate.

Significance level (α)

Desired power