Cohen’s d and Hedges’ g
Compare two means on a pooled standard-deviation scale.
Your numbers
Cohen’s d
Use consistent units. The result follows the assumptions you enter.
Scenario comparison
Up to three snapshots in this tab. Loading one replaces the current inputs.
Formula
d=(μA−μB)/sp; g≈d[1−3/(4df−1)]
Compare two means on a pooled standard-deviation scale.
Worked example
- Group A mean
- 10
- Group B mean
- 8
- Group A sample SD
- 2
- Group B sample SD
- 2
- Group A sample size
- 20
- Group B sample size
- 20
- Cohen’s d
- 1
- Hedges’ g (approximate correction)
- 0.980132450331
- Pooled sample SD
- 2
Scope and limitations
Use consistent units. The result follows the assumptions you enter.
Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.
Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.
Formula version: 17deede3f8f9 · Example checked: