The body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It is defined as the weight in kilograms divided by the square of the height in meters. For example, a person who weighs 70 kilograms and is 1.75 meters tall has a BMI of 22.6.
BMI is a useful tool for screening for weight-related health problems such as obesity, heart disease, stroke, type 2 diabetes, and some types of cancer. It is also used to track changes in body weight over time.