Body mass index (BMI) is a measure of body fat based on height and weight. It is used to screen for weight-related health problems such as obesity, underweight, and eating disorders.
BMI is calculated by dividing weight in kilograms by the square of height in meters. For example, a person who weighs 68 kg and is 1.7 m tall would have a BMI of 23.6. This is considered to be a healthy weight.