Calculating the effect size using Hedges' h Table of Contents Toggle Hedges g calculatorCalculate Cohen's d Hedges g calculator Media group 1 (M1): Standard deviation group 1 (SD1): N group 1 (n1): Media group 2 (M2): Standard deviation group 2 (SD2): N group 2 (n2): Calculate Hedges h values: 0.2: Small effect size. 0.5: Average effect size. 0.8: Large effect size. Cohen's d calculator Calculate Cohen's d Media group 1: Media group 2: SD group 1: SD group 2: Calculate Values of the d in Cohen: 0.2: Small 0.5: Medium 0.8: Large