The term BMI is often used when discussing the obesity epidemic, but what is BMI?
BMI stands for Body Mass Index. It is a number that shows body weight adjusted for height. BMI can be calculated with simple math using inches and pounds, or meters and kilograms. For adults aged 20 years or older, BMI falls into one of these categories: underweight, normal, overweight, or obese.
Your body mass index (”BMI”) measures your height/weight ratio. It is your weight in kilograms divided by the square of your height in meters.
For instance, if your height is 1.82 meters, the divisor of the calculation will be (1.82 * 1.82) = 3.3124. If you weigh 70.5 kilograms, then your BMI is 21.3 (70.5 / 3.3124).
People with BMIs between 19 and 22 live longest. Death rates are noticeably higher for people with indexes 25 and above. (5/1/2001: The U.S. government recently changed these ranges to a minimum of 20 and a maximum of 24. I encourage you to take these numbers with a grain of salt; they are not as accurate as they sound.)
- This is the American version of the calculation.[height in feet and inches]
- If you’re not American, click here for a version of this page that accepts metric values.
Revision date: June 18, 2011
Last revised: by Sebastian Scheller, MD, ScD