Body Mass Index

Body mass index (BMI) is an indirect measure of body fat in an individual that is determined using a person's height and weight. Because the calculation only requires two measurements, body mass index is an easy tool to use for screening weight categories that may lead to health problems. A normal body mass index for adults of at least 20 years of age ranges from 18.5 to 24.9.

 

What Is Body Mass Index?

Over 100 million adult Americans are overweight or obese. Being overweight or obese increases a person's chances for developing many diseases, especially heart disease, stroke, diabetes, and cancer. How can someone determine if he or she is overweight or obese? Research on obesity has shown that a calculation called body mass index (or BMI for short) can be used to measure body fatness.
 
Body mass index does not measure body fat directly, but it corresponds closely to direct measures of body fat. Therefore, body mass index can be considered an alternative for direct measures of body fat.
 
Body mass index is determined using a person's height and weight. Because the BMI calculation requires only these two simple pieces of information, it is an inexpensive and easy-to-use method of screening for weight categories that may lead to health problems (see Health Effects of Obesity).
 

How Is Body Mass Index Calculated?

There are a few ways to calculate body mass index:
 
  • Use the BMI formula
  • Use the BMI chart
  • Use the BMI calculator.
     
Any of these three methods will get the same body mass index result. Everyone can use one of these three methods, regardless of age, gender, race, or ethnicity. There is no specific BMI chart for women or men.
 
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD