Body Mass Index

Your Body Mass Index (BMI) is a calculation based on your height and weight that you can use to determine if you are underweight, at a healthy weight, overweight or obese. It's easy to do and quite accurate unless you are very muscular or if you are very obese.

What Does My BMI Mean?

Your BMI indicates your weight status:

Below 18.5 Underweight
18.5 – 24.9 Normal
25.0 – 29.9 Overweight
30.0 and Above Obese

Why Do I Need to Know My BMI?

A BMI of 25 or above is a risk factor for overweight and obesity related diseases such as cardiovascular disease, osteoarthritis, some types of cancer and type II diabetes. A low BMI -- under 18 -- increases your risk for osteoporosis or may be a sign of a health problem. If you have a BMI of above 27 or below 18, you should see your doctor to have any additional risk factors assessed and for guidance on how to lose (or gain) weight.

How Do I Calculate My BMI?

You can use the formula in English:

Your Weight in Pounds / (Your Height in Inches)² x 703

or in Metric:

Your Weight in Kilograms / (Height in Meters)²

Or simply enter your height and weight into a BMI calculator that will do the math for you:

English BMI Calculator
Metric BMI Calculator

Will This Work For Children Too?

You can calculate the BMI for children. However, using a BMI percentile may be more useful. Learn how to calculate a child's BMI and BMI percentile.

_Sources:

Centers for Disease Control and Prevention. "About BMI for Adults." Updated 1/2009.

Asomaning K, Bertone-Johnson ER, Nasca PC, Hooven F, Pekow PS. "The association between body mass index and osteoporosis in patients referred for a bone mineral density examination." J Womens Health (Larchmt). 2006 Nov;15(9):1028-34.