Ponderal Index Calculator
The Ponderal Index divides body mass by the cube of height (kg/m³) rather than the square used by BMI, giving a better comparison across very different body heights. Enter your weight and height to see your PI and category.
Unit system
kg
cm
Normal weight
- 1
Height in metres
175 cm ÷ 100 = 1.75 - 2
Height cubed
1.75³ = 5.359375 - 3
Ponderal Index
70 ÷ 5.359375 = 13.06
How does this calculator work?
The Ponderal Index = mass (kg) ÷ height³ (m³). Unlike BMI (mass/height²), it scales correctly with body dimensions across different heights. Normal range is roughly 11–14 kg/m³. It does not distinguish fat from muscle and thresholds are not universally standardised — use it alongside other measures and professional advice.
Formula
How this is calculated
The Ponderal Index (also called the Corpulence Index or Rohrer Index) is calculated as PI = mass / height³. Because body mass scales roughly with the cube of linear dimensions (volume ~ length³), dividing by height³ removes most of the height bias that affects BMI (which divides by height², systematically underrating tall people and overrating short ones).
The classification thresholds used here are commonly cited in the medical literature (PI < 11 underweight, 11–14 normal, 14–17 overweight, > 17 obese), though they are not universally standardised in the way BMI cut-offs are (18.5/25/30). Always discuss body-composition results with a healthcare professional — the PI, like BMI, does not distinguish fat mass from muscle or bone, and varies across ethnic groups and age ranges.
For reference, BMI is shown alongside the PI so you can compare how the two indices classify the same measurements. Significant differences between the two arise mainly at extreme heights.
Frequently asked questions
BMI = mass/height² systematically overestimates fatness in tall individuals because real bodies scale in three dimensions. The PI = mass/height³ accounts for that cubic scaling, so tall and short people are compared on a more level footing.
No — the PI has no single universally adopted cut-off system the way BMI's 18.5/25/30 thresholds are. The ranges shown here (< 11 / 11–14 / 14–17 / > 17 kg/m³) are widely cited but should be treated as guidance rather than clinical thresholds.
Yes. The PI is widely used in neonatology (where it is sometimes called the neonatal Ponderal Index) to assess whether a newborn is appropriately grown for its length, since BMI cut-offs derived from adult populations are not applicable to infants.
Also known as
TG we-Calculate Editorial Team. (2026). Ponderal Index Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ponderal-index-calculator
TG we-Calculate Editorial Team. "Ponderal Index Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/ponderal-index-calculator.
TG we-Calculate Editorial Team, "Ponderal Index Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ponderal-index-calculator
@misc{wecalculate_ponderal_index_calculator, title = {Ponderal Index Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ponderal-index-calculator}}, year = {2026}, note = {TG we-Calculate} }
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