Body mass index (BMI) or Quetelet Index is a statistical measure of the weight of a person scaled according to height. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing "social physics".

Body Mass Index Calculator

Enter your height and weight and then click Calculate.

Your BMI will help you decide if you are at a healthy weight.

Height:

ft

in

Weight:

lbs

=

Underweight less than 18.5	Normal weight 18.5-24.9	Overweight 25-29.9	Obesity 30 or greater
A BMI of less than 18.5 is considered underweight. You may not be getting enough of the right foods. This can lead to a weakened immune system, fragile bones, and other health problems.	A BMI between 18.5 and 24.9 falls within the normal weight range. But it's still important to eat right, exercise and get regular checkups.	A BMI between 25 and 29.9 falls within the overweight range. Being overweight increases your risk for heart disease, diabetes, and other serious health problems. See your doctor to learn how to manage your weight.	A BMI of 30 or more is considered obese. Being obese increases your risk for serious conditions such as heart disease, diabetes, and high blood pressure. See your doctor to learn how to manage your weight.

BMI is a reliable indicator of total body fat, which is related to the risk of disease and death. The score is valid for both men and women but it does have some limits. The limits are:

• It may overestimate body fat in athletes and others who have a muscular build.
• It may underestimate body fat in older persons and others who have lost muscle mass.
• You could have a normal BMI and have poor nutrition.

Limitations and shortcomings

The medical establishment has generally acknowledged some shortcomings of BMI. Because the BMI is dependent only upon net weight and height, it makes simplistic assumptions about distribution of muscle and bone mass, and thus may overestimate adiposity on those with more lean body mass (e.g. athletes) while underestimating adiposity on those with less lean body mass (e.g. the elderly).

In fact, some argue that the error in the BMI is significant and so pervasive that it is not generally useful in evaluation of health. Due to these limitations, body composition for athletes is often better calculated using measures of body fat, as determined by such techniques as skinfold measurements or underwater weighing.