The ponderal index, or Rohrer’s index, is similar to BMI but uses the cube of height.
How to use the Ponderal Index Calculator
- Weight
- Height
Results update as you type, and every field accepts the units shown in its menu.
How it works
Divide weight in kilograms by height in metres cubed. Typical adult values are about 11–15 kg/m³.
Inputs explained
| Field | What to enter |
|---|---|
| Weight | Units: kg, lb, g, oz, st |
| Height | Units: cm, m, mm, in, ft |
What each result means
- Ponderal index = [Weight] ÷ ([Height]÷100)^3
- BMI for comparison = [Weight] ÷ ([Height]÷100)^2
Example values
How the main result changes when Weight changes and everything else stays at the example values above:
| Weight (kg) | Ponderal index (kg/m³) |
|---|---|
| 35 | 6.53 |
| 52.5 | 9.8 |
| 70 | 13.06 |
| 87.5 | 16.33 |
| 105 | 19.59 |
| 140 | 26.12 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
PI = weight (kg) ÷ height (m)³Worked example
Inputs — Weight: 70 kg; Height: 175 cm.
Results — Ponderal index = 13.06 kg/m³; BMI for comparison = 22.9 kg/m².
Frequently asked questions
How is it used for babies?
Newborn ponderal index (in g/cm³ × 100) helps identify growth restriction.
Why cube the height?
Body volume scales roughly with the cube of height.
What formula does the Ponderal Index Calculator use?
PI = weight (kg) ÷ height (m)³.