Body Mass Index (BMI) is index used to evaluate a person's weight. It does not take into account body composition. It is simply based on weight and height. So two people with the same the BMI may have different percentages of fat and lean tissue. However, measuring BMI is easier than measuring body fat percentage. And a high BMI could indicate risk of diseases including cardiovascular diseases and diabetes.

Unlike Waist-to-Height Ratio, BMI does not take into account the location where fat is stored. Some studies indicate that fat stored around the waist can increase the risk of cardiovascular disease.

Body Mass Index has the following four weight status categories.