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Find your Body Mass Index

Body mass index (BMI) is a tool used to measure body fat. It is based on your height and weight. Your doctor may use your BMI to see if you are a healthy weight. The doctor takes your BMI number and compares it to the BMI numbers of other people your age. The comparison is called a percentile.

Choose your age:

Enter your weight, in pounds.
(For example, 110)

Enter your height, in inches.
(For example, 62, instead of 5ft 2in)

This calculator is designed only for girls between the ages of 10 and 16 who are not pregnant. Make sure to talk with your doctor about your BMI.

To help understand your BMI number, look at Mary's BMI Chart, below.

Mary's BMI Chart

After entering her height (60 inches) and weight (90 pounds) into the BMI calculator, Mary learned that her BMI is 18. She found her age (15) on the left side of the graph and her BMI on the bottom of the graph. Where the two points meet, at the pink star, shows that Mary's BMI is within a range that is healthy for her height, weight, and age.

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Understanding BMI

BMI is usually a very good measure, but it also can miss the mark. That's partly because your weight doesn't indicate whether it's coming from muscle, which is healthy, or from fat, which is less healthy. For example, a person can have a BMI that falls in the healthy range, but she may have lots of fat and little muscle, which isn't very healthy. Another person might have a BMI above the healthy range, but she could be fine if she has lots of muscle and just a little fat.

What if your BMI is below the healthy range? It is possible that you are fine, but it's possible that you are not getting the nutrients your body needs. Keep in mind that your BMI may change over time, so you may want to track it over a period of months.

Talk with your doctor to determine the healthiest weight for you. You can print your BMI results and share them with your doctor.

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The formula used for BMI calculation on this page is:
BMI = ( weight in pounds ÷ (height in inches)² ) x 703

Content last reviewed November 05, 2013
Page last updated April 09, 2014

U.S. Department of Health and Human Services, Office on Women's Health.