The Ponderal Index is a measure of leanness of a person calculated as a relationship between mass and height.
It was first proposed 1921 as "Corpulence Index" by Rohrer. It is similar to the body mass index

Body mass index

The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...

, but the mass is normalized with the third power of body height rather than the second power.
with in kg (kilograms) and in m (meters), giving a measure with the same dimensions

Dimensional analysis

In physics and all science, dimensional analysis is a tool to find or check relations among physical quantities by using their dimensions. The dimension of a physical quantity is the combination of the basic physical dimensions which describe it; for example, speed has the dimension length per...

 as density

Density

The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

. The ponderal index yields valid results even for very short and very tall persons. Because of this property, it is most commonly used in pediatrics

Pediatrics

Pediatrics or paediatrics is the branch of medicine that deals with the medical care of infants, children, and adolescents. A medical practitioner who specializes in this area is known as a pediatrician or paediatrician...

. The normal values for infants are about twice as high as for adults, which is the result of their relatively short legs.

The ponderal index is variously defined (the first definition should be preferred due to the use of SI-units

International System of Units

The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...

 kg and m) as follows:

Formula	Units for mass (body weight)	Units for height (or length)	Values corresponding to "normal" BMI Body mass index The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing... in a 180 cm tall person
	kilograms	metres	10.3 to 13.9, 24 for 12 month old infant
	grams	centimetres	2.4 for 12 month old infant
	kilograms	centimetres	21.75 to 24.0
	kilograms	centimetres	2.175 to 2.4
	pounds	inches	12.49 to 13.92

External links

• Online Ponderal Index Calculator, which uses the first definition.
• Ponderal Index Calculator, which uses metric values. (german site)