A calculated measure of body weight relative to height, commonly used as a population-level screening measure related to body size.
BMI is calculated by dividing weight in kilograms by height in meters squared. In adults, commonly used categories classify BMI into ranges such as underweight, healthy weight, overweight, and obesity.
BMI is useful for population studies and as one piece of individual health assessment, but it does not directly measure body fat or distinguish muscle from fat. Interpretation can also vary with age, sex, ethnicity, and other factors.
QUICK FACT
BMI is a screening measure, not a diagnosis of health or body-fatness. A muscular person, for example, may have a high BMI without having excess body fat.
COMMONLY CONFUSED WITH
Body fat percentage: the proportion of body weight made up of fat; BMI does not directly measure this.
SEE ALSO