Body mass index (BMI) is a measure of body fat based on height and weight. It is calculated by dividing weight in kilograms by the square of height in meters (kg/m2). BMI is used to assess body weight in relation to health risk and is often used to identify overweight and obesity.
However, BMI does not take into account muscle mass, which can lead to inaccurate results for people who are muscular. This is because muscle is denser than fat, so people with more muscle may have a higher BMI than people with less muscle, even if they have the same amount of body fat.