Ponderal Index Calculator

Calculate Ponderal Index (Rohrer index) and convert it to height-adjusted BMI-equivalent categories.

ImperialMetric

Height

5 ft 9 in

Weight

180 lbs

15.15

Overweight Equivalent

Equivalent to BMI 25.0-29.9 for your current height.

Ponderal Index

15.15

Equivalent BMI

26.6

Healthy PI Range

10.55-14.2

Height-Adjusted Category

Overweight Equivalent

6.610.614.317.12022.826.8

UnderHealthyOverClass IClass IIClass III

Overweight Equivalent

Ponderal Index Interpretation

Ranges are adjusted to your current height so they align with equivalent adult BMI categories.

RANGE	CATEGORY	WHAT IT USUALLY MEANS
0-10.57	Underweight Equivalent Ponderal-index equivalent to BMI below 18.5 at your current height.	Ponderal-index equivalent to BMI below 18.5 at your current height.
10.57-14.29	Healthy Equivalent Equivalent to BMI 18.5-24.9 for your current height.	Equivalent to BMI 18.5-24.9 for your current height.
14.29-17.14	Overweight Equivalent Equivalent to BMI 25.0-29.9 for your current height.	Equivalent to BMI 25.0-29.9 for your current height.
17.14-20	Obesity I Equivalent Equivalent to BMI 30.0-34.9 for your current height.	Equivalent to BMI 30.0-34.9 for your current height.
20-22.86	Obesity II Equivalent Equivalent to BMI 35.0-39.9 for your current height.	Equivalent to BMI 35.0-39.9 for your current height.
22.86+	Obesity III Equivalent Equivalent to BMI >=40.0 for your current height.	Equivalent to BMI >=40.0 for your current height.

What Is Ponderal Index?

Ponderal Index (PI) is calculated as weight (kg) divided by height cubed (m3). Compared with BMI, PI scales weight by an additional power of height and can be useful in certain anthropometric comparisons.

Why Height-Adjusted PI Ranges Matter

Unlike BMI cutoffs, PI boundaries change with height when you map to equivalent adult BMI categories. This calculator updates interpretation ranges using your current height so the classification remains comparable.

For direct BMI outputs, use the BMI Calculator. For broader weight targets, pair with the Ideal Weight Calculator.

If you are planning calorie targets around those goals, run the TDEE Calculator and Calorie Deficit Calculator.

References

Rohrer/Ponderal index discussion in anthropometric literature:PMC Review Including Rohrer Index Context
CDC adult BMI category reference (used for equivalent mapping):CDC BMI Categories

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BMI Calculator

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Overweight Calculator

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Ideal Weight Calculator

Compare healthy BMI range and Devine ideal body weight.

TDEE Calculator

Estimate total daily energy expenditure from BMR equation and activity level.