What is Ponderal Index?
The Ponderal Index (PI), also called Rohrer's Index or Corpulence Index, is calculated as weight/height³. Unlike BMI which uses height², PI is less affected by height variations, making it more accurate for very tall or very short individuals.
PI vs BMI
BMI tends to overestimate body fat in tall people and underestimate it in short people. PI corrects for this by using height cubed instead of squared. Normal PI ranges from 12-14 kg/m³, compared to BMI's 18.5-24.9 kg/m².
When to Use PI
PI is particularly useful for populations with significant height variations, for newborns and children, and for research comparing populations with different average heights. It's less commonly used clinically than BMI but provides valuable additional information.
Quick Tips
- BMI alone doesn't reflect overall health
- TDEE varies based on activity level
- Consult a healthcare professional for medical decisions
Frequently Asked Questions
For very tall or short people, yes. For average heights, both work similarly.
Generally 12-14 kg/m³ is considered normal for adults.
It better represents the relationship between linear growth and weight gain.
Less common than BMI, but used in pediatrics and research settings.
If you're unusually tall or short, PI provides additional useful information.