Is BMI a medical diagnosis?

No, it is a screening tool. For a full assessment, consult a healthcare provider who considers muscle mass and other factors.

What is the Ponderal Index?

The Ponderal Index is similar to BMI but uses the cube of height. It is often considered more consistent across different body types.

Calculate your BMI, BMI Prime, Ponderal Index (PI) and Waist-to-Height Ratio.

Height (cm)

Enter your height (cm or in)

Weight (kg)

Enter your current weight (kg or lbs)

Age

Needed to interpret some indices (children/teens).

Waist circumference (cm)

Optional. Useful for the Waist-to-Height Ratio (WHtR).

22.5

Normal weight

BMI Prime0.9

Ponderal Index13.2

Body Mass Index (BMI) is a simple weight-to-height ratio used to estimate body fat and health risks.

Underweight

< 18.5

Normal weight

18.5 - 24.9

Overweight

25 - 29.9

Obesity

≥ 30

BMI Prime: BMI ÷ 25 (values > 1 indicate BMI is above the upper limit of 'normal').
Ponderal Index (PI): weight / height³ (provides a more accurate scale for very tall or short individuals).
WHtR: often a better predictor of cardio-metabolic risk than BMI alone.

bmi calculatorbody mass indexbmi primeponderal indexwhtrhealthy weightbmi categories

Is BMI a medical diagnosis?: No, it is a screening tool. For a full assessment, consult a healthcare provider who considers muscle mass and other factors.
What is the Ponderal Index?: The Ponderal Index is similar to BMI but uses the cube of height. It is often considered more consistent across different body types.