Body Mass Index (BMI)

Body mass index, or BMI, is a calculation based on your height and weight to place you in a weight category: underweight, normal weight, overweight, or obese.

BMI can be a useful starting measure to identify your weight classification and risk of comorbidities.

BMI is not relevant if you are under 18 years or pregnant.

BMI is a very general measure that places you in 1 of 6 broad weight categories – underweight, normal weight, overweight, obese.

BMI Calculator

Units Metric Imperial

Height Height

Weight Weight

Height Height

Weight Weight

BMI result

Your Body Mass Index Result

Excess Weight Result

BMI Result

BMI Classes and Comorbidity Risks

Classification
BMI
Risk of Comorbidities

Underweight
Less than 18
Increased

Normal weight
18-25
Low

Overweight
25-30
Increased

Clase I Obesity
30-35
Moderate

Clase II Obesity
35-40
Severe

Clase III Obesity
40 or greater
Very severe

Fat predominantly distributed around the waist is also a risk factor for health complications such as cardiovascular disease and type II diabetes. Fat predominantly deposited around the hips and buttocks doesn't have this same risk.