Your Body Mass Index (BMI) is a number calculated from your weight and height. Although BMI does not measure body fat directly, research has shown that BMI is a reliable indicator of body fatness for people, and it correlates to more high-tech measures of body fat, such as underwater weighing and dual energy x-ray absorptiometry (DXA). BMI has the added advantage of being inexpensive and easy to perform. This number can help your physician identify possible weight problems.
How Can You Calculate Your BMI? Show More Show Less
Using the Metric System
With the metric system, the formula for BMI is weight in kilograms divided by height in meters squared. Since height is commonly measured in centimeters, divide height in centimeters by 100 to obtain height in meters:
BMI = Weight ÷ height2
Example: Height = 165 cm (1.65 m), Weight = 68 kg
Calculation: 68 ÷ (1.65)2 = 24.98
Using Pounds and Inches
To calculate BMI using pounds and inches, you divide your weight in pounds by height in inches squared, then multiply by a conversion factor of 703.
BMI = Weight ÷ height2 x 703
Example: Weight = 150 lbs, Height = 5’5″ (65″)
Calculation: [150 ÷ (65)2] x 703 = 24.96
What If I Don’t Want to Do the Math? Show More Show Less
How Do I Interpret My BMI? Show More Show Less
(Note: calculating and interpreting BMI results for children and teens is a different process. If you need information and guidance about calculations for someone under the age of 20, visit the Centers for Disease Control website at this address: http://apps.nccd.cdc.gov/dnpabmi/Calculator.aspx)
The standard weight status categories associated with BMI ranges for adults are shown in the following table.
- Below 18.5 — Underweight
- 18.5 – 24.9 — Normal
- 25.0 – 29.9 — Overweight
- 30.0 and Above — Obese