Effect Size Calculator

Calculate Cohen's d effect size to measure the standardized difference between two group means. Shows interpretation (negligible, small, medium, large) and pooled standard deviation.

How to Use Effect Size Calculator

Enter the mean and standard deviation for each group. Optionally provide sample sizes for weighted pooled SD calculation. Click Calculate to get Cohen's d value with interpretation of effect magnitude.

Step-by-Step Instructions

  1. Enter Group 1 mean and standard deviation
  2. Enter Group 2 mean and standard deviation
  3. Optionally enter sample sizes for each group
  4. Click Calculate to view Cohen's d and interpretation

Related Tools

More Free Tools