BMI calculator
Calculate your body mass index from height and weight, with adult reference ranges and clearly explained limitations.
Height and weight
Enter your measurements. Imperial units are selected by default.
Height
Your result
Your BMI
-
Underweight< 18.5
Normal weight18.5 – 24.9
Overweight25 – 29.9
Obesity≥ 30
Weight range corresponding to BMI 18.5–24.9
A mathematical reference for your height, not a personalised weight target.
BMI Prime
Ponderal index
BMI Prime compares your BMI with 25 (below 1: under the overweight threshold). The ponderal index, weight ÷ height³, stays steadier for very tall or very short people.
Add the waist-to-hip ratioBMI does not show where fat sits: the waist-to-hip ratio spots abdominal fat, more closely linked with cardiovascular risk.Method & sources
BMI is calculated from weight and height. The displayed categories use the World Health Organization adult BMI reference ranges.
Formula
BMI = weight (kg) ÷ height² (m)Limitations
- BMI does not distinguish body fat from muscle mass.
- By itself, it does not account for fat distribution, age or body composition.
- Adult thresholds should not be used for children, adolescents or during pregnancy.
Method & sources
BMI is calculated from weight and height. The displayed categories use the World Health Organization adult BMI reference ranges.
Formula
BMI = 703 × weight (lb) ÷ height² (in)Limitations
- BMI does not distinguish body fat from muscle mass.
- By itself, it does not account for fat distribution, age or body composition.
- Adult thresholds should not be used for children, adolescents or during pregnancy.