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Understanding Body Mass Index (BMI)

Body mass index (BMI) is a ratio of your height to your weight. The BMI is a measure of overweight that is corrected for height. Knowing your BMI is a way of finding whether you are at a healthy weight. The higher your BMI, the greater your risk for weight-related health problems.

What BMI Means

  • BMI below 18.5: Underweight

  • BMI 18.5 to 24.9: Healthy weight or "ideal body weight" 

  • BMI 25 to 29.9: Overweight

  • BMI 30 and over: Obese

  • BMI 40 and over: Severe obesity 

  • BMI 50 and over: Super obesity 

Using the BMI Chart

To figure your BMI, find your height and weight (or the numbers closest to them) on the chart below. Follow each column of numbers to where your height and weight meet on the chart. That is your BMI. You can also calculate your BMI using the formula below.

Body Mass Index table showing BMI numbers for height and weight.

Using the BMI Formula

Example

Multiply your weight in pounds by 703.

160 pounds x 703= 112480

Divide the answer by your height in inches.

112480 ÷ 63 inches= 1785

Divide this number by your height in inches again. This is your BMI.

1785 ÷ 63 inches= BMI of 28

Online Medical Reviewer: Grantham, Paula, RN, BSN
Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Last Review Date: 2/23/2014
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