Calculate the Ponderal Index, an alternative to BMI that divides weight by height cubed instead of squared.
How It Works
How Ponderal Index Calculator Works
Where BMI divides weight by height squared, the Ponderal Index divides by height cubed, which changes how it treats unusually tall or short people — it's used in two quite different contexts: an adult version (height in cm, weight in kg, scaled by a million) and a newborn version (height in cm, weight in grams, scaled by 100) used by pediatricians to flag small-for-date babies.
Worked Example
See It In Action
An adult at 170 cm and 43 kg has a Ponderal Index of about 8.75, which falls below the normal range and reads as underweight on this scale.
FAQ
Frequently Asked Questions
Why are there separate Adult and Child modes?
The two use different weight units and scaling factors entirely — adult PI is calibrated for kilograms, while the newborn version is calibrated for grams, since a full-term baby's weight is a very different order of magnitude.
Is the Ponderal Index better than BMI?
For very tall or very short adults, it's sometimes considered a fairer measure since cubing height changes how extremes are weighted, but it's used far less often than BMI outside of the newborn screening context.
