Health and Medicine

Health Hazards and Risks

How is body mass index (BMI) calculated?

The National Heart, Lung, and Blood Institute (NHLBI), in cooperation with the National Institute of Diabetes and Digestive and Kidney Diseases, released guidelines for weight for adults in 1998. These guidelines define degrees of overweight and obesity in terms of body mass index (BMI). Body mass index is based on weight and height and is strongly correlated with total body fat content. It is used to assess an individual’s weight-related level of risk for heart disease, diabetes, and high blood pressure. Very muscular individuals, such as athletes, may have a high BMI without health risks.

185 pounds × 703 = 130,055

702 = 4,900

130,055/4,900 = 26.5

Evaluating BMI in Adults
BMI Weight Status
Below 18.5 Underweight
18.5–24.9 Normal
25.0–29.9 Overweight
30.0 and above Obese
Evaluating BMI in Children and Teenagers Ages 2 to 20
BMI Weight Status
BMI-for-age < 5th=""> Underweight
BMI-for-age 5th percentile to < 85th=""> Normal
BMI-for-age 85th percentile to < 95th=""> At risk of being overweight
BMI-for-age < 95th=""> Overweight


This is a web preview of the "The Handy Science Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App