Body mass index (BMI) is a measure of body fat based on height and weight that applies to children and teenagers. It’s calculated by dividing a person’s weight (in kilograms) by the square of their height (in meters). For example, a child who weighs 50 kilograms and is 1.5 meters tall would have a BMI of 22.2.
BMI is a useful tool for assessing whether a child is underweight, overweight, or obese. It can also be used to track a child’s growth and development. BMI was developed in the 19th century by Adolphe Quetelet, a Belgian statistician.