Effect Size Calculator
Convert Cohen's d, r, odds ratio, eta-squared, and Cohen's f with assumptions shown.
At a glance
- Computes
- Conversions between Cohen's d, r, odds ratio, eta-squared, and Cohen's f.
- You supply
- One effect size, its type, and the group-size assumption to convert under.
- Use when
- A paper reports one effect metric and you need it in another for comparison.
- Assumes
- Equal group sizes unless you set a ratio; conversions are approximations.
Primary equivalent
Enter an effect
Assumptions appear in the table.
| Metric | Value | Formula | Assumption |
|---|
r = d / sqrt(d^2 + 4), OR = exp(d * pi / sqrt(3))
How?
How this is calculated
Equal-group conversions use the standard relationship between Cohen's d and the point-biserial correlation. Odds-ratio conversion uses Chinn's logistic approximation, so the table marks it as an approximation.
Formula: r = d / sqrt(d^2 + 4), OR = exp(d * pi / sqrt(3))
This page converts one effect size between units. Combining several studies into one estimate is a different operation with different assumptions: the studies get weights, the between-study variance has to be estimated, and the answer needs a heterogeneity statement beside it. The meta-analysis instrument does that and draws the forest plot.
Sources
- Effect size overview. Wikipedia. Retrieved .
- Chinn odds-ratio approximation. Statistics in Medicine. Retrieved .
Method last reviewed