The Ponderal Index Calculator estimates body composition using weight divided by height cubed, giving a figure in kg/m³ that holds up better than BMI at the extremes of height. It is also known as the Corpulence Index or Rohrer Index.
How it works
The Ponderal Index uses the formula:
Ponderal Index = mass (kg) ÷ height (m)³
Cubing height (rather than squaring it, as BMI does) keeps the index roughly
constant as a person scales up or down in size. A 70 kg adult who is 1.75 m tall
has a Ponderal Index of 70 ÷ 1.75³ = 70 ÷ 5.359 ≈ 13.1 kg/m³.
Interpreting your result
| Ponderal Index (kg/m³) | General interpretation |
|---|---|
| Below 11 | Underweight range |
| 11 – 15 | Normal range |
| Above 15 | Overweight range |
These bands are a screening guide for adults, not a medical diagnosis. Athletes with high muscle mass can read high without excess fat, and the index says nothing about where body fat is stored.
Ponderal Index vs BMI
BMI works well across most of the population but drifts at the tails: a 2.0 m basketball player can be flagged overweight by BMI while carrying little fat, and a 1.5 m adult can be reassured by a BMI that hides excess weight. Because the Ponderal Index divides by height cubed, it removes most of that height bias, which is why clinicians sometimes reach for it for very tall or very short people, and in some infant and child growth contexts.