# Ponderal Index Calculator

URL: https://speedycalculator.com/calculators/health/ponderal-index/
Last updated: 2026-10-25

> The ponderal index calculator divides weight by height cubed. Because it scales with body volume, it stays more consistent than BMI for very short or very tall people and is used for newborns.

## Inputs

- Weight (kg, lb, g, oz, st)
- Height (cm, m, mm, in, ft)

## Results

- Ponderal index
- BMI for comparison

## Formula

```
PI = weight (kg) ÷ height (m)³
```

## Explanation

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

FieldWhat to enterWeightUnits: kg, lb, g, oz, stHeightUnits: 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)356.5352.59.87013.0687.516.3310519.5914026.12
*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.*

## Worked example

Inputs — Weight: 70 kg; Height: 175 cm.

Results — **Ponderal index = 13.06 kg/m³**; BMI for comparison = 22.9 kg/m².

## FAQ

**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.