Body mass index (BMI) is a measure of body fat based on height and weight. It is calculated by dividing a person’s weight in kilograms by the square of their height in meters. For example, a person who weighs 70 kg and is 1.75 m tall would have a BMI of 22.2.
BMI is a convenient and inexpensive way to screen for obesity. It is also used to track weight loss progress and to assess the risk of developing obesity-related diseases, such as heart disease, stroke, type 2 diabetes, and some types of cancer. BMI was first developed in the 19th century by Belgian statistician Adolphe Quetelet.