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BMI Tools

BMI is an estimate of body fat and a good measure of your patients' risk for diseases that can occur with overweight and obesity. For adults, a healthy weight is defined as the appropriate body weight in relation to height. This ratio of weight to height is known as the body mass index (BMI). People who are overweight (BMI of 25–29.9) have too much body weight for their height. People who are obese (BMI of 30 or above) almost always have a large amount of body fat in relation to their height. The higher the BMI, the higher the risk for heart disease, high blood pressure, type 2 diabetes, gallstones, osteoarthritis, sleep apnea, and certain cancers (e.g., colon, breast, endometrial, and gallbladder).

Although BMI can be used for most men and women, it does have some limits:

  • It may overestimate body fat in athletes and others who have a muscular build.
  • It may underestimate body fat in older persons and others who have lost muscle.

BMI for children and teens, 2 to 20 years old, is determined by using a BMI table that compares their weight and height along with growth charts. The growth charts use a child's BMI, age, and gender to produce a BMI percentile. A child or teen who is between the 85th and 95th percentile on the growth chart is considered overweight. A child or teen who is at the 95th percentile or above is considered obese. For more information about BMI percentile and growth charts for children, visit and NHLBI's We Can! Web pages.

BMI Calculator

The BMI Calculator is an easy-to-use online tool to help you estimate your adult patients' body fat. The BMI calculator uses Standard or Metric measures and is available in English or Spanish.

Check your patient's BMI

BMI Calculator iPhone Application

The National Heart, Lung, and Blood Institute's BMI (Body Mass Index) calculator is a useful tool to screen for weight categories that may lead to health problems.  The downloadable phone application puts the fully functioning calculator right on your phone, along with links to resources on the NHLBI site.

Download the BMI Calculator iPhone App


BMI Calculator in Palm OS Format

The BMI Calculator is also available as a Palm Operating System (Palm OS) and PocketPC application. In addition to the calculator (in English only), this tool includes a BMI classification table for adults and provides additional information about BMI from the Evidence Report and Practical Guide.

Download our BMI Calculator

BMI Table

The BMI Table is a static tool to help you estimate your patients' body fat.

Use the BMI Table




Healthy Weight Tip

Use the BMI calculator to assess overweight and obesity. Body weight alone can be used to follow weight loss and to determine the effectiveness of therapy.

Help Your Patients Check Their BMI

Screen shot of a BMI calculatorThe BMI Calculator is an easy-to-use online tool to help estimate body fat. It is also good a measure of patients' risk of heart diseases that occur with more body fat. The higher your BMI, the higher your risk of obesity-related disease.

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