Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It’s used to categorize people as underweight, normal weight, overweight, or obese.
BMI is calculated by dividing a person’s weight in kilograms by the square of their height in meters. For example, a person who is 1.7 meters tall and weighs 70 kilograms has a BMI of 24.2.