Statistical Power Calculator

Calculate the statistical power of your experiment to determine the probability of detecting an effect if one exists.

Sample Size (per variant)

Number of observations per variant

Baseline Conversion Rate (%)

Current conversion rate

Effect Size to Detect (%)

Expected relative change

Significance Level (%)

Typically 5% (95% confidence)

What is statistical power?

Statistical power is the probability of detecting an effect when there truly is one. A power of 80% or higher is generally recommended for reliable experiments.