How to Measure Your Body Mass Index (BMI) and Waist Circumference

Overweight, Obesity and Body Fat Distribution Measures

Scale and tape measure for BMI
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Health care providers use body mass index (BMI) and waist circumference measures to assess a person's risk of developing diabetes, arthritis, and other health conditions. More than one-third (34.9% or 78.6 million) of U.S. adults are obese. Two easy measures, body mass index (BMI) and waist circumference, provide useful estimates of overweight, obesity, and body fat distribution. Learn how to measure your BMI and waist circumference, and what these measures mean in terms of your health.

  1. BMI measures your weight in relation to your height, and is closely associated with measures of body fat. You can calculate your BMI using this formula: BMI equals a person's weight in pounds divided by their height in inches squared, multiplied by 703. For example, for someone who is 5 feet, 7 inches tall (67") and weighs 220 pounds, the calculation would look like this: 220 divided by 4489 (67" X 67") multiplied by 703 = 34.45 BMI. Or, you can use this handy BMI Calculator.

  2. Body Mass Index (BMI) Chart:
    • A person with a BMI of 18.5 to 24.9 is considered healthy.
    • A person with a BMI of 25 to 29.9 is considered overweight.
    • A person with a BMI of 30 or more is considered obese.
  3. Because BMI does not show the difference between fat and muscle, it does not always accurately predict when weight could lead to health problems. For example, someone with a lot of muscle (such as a bodybuilder) may have a BMI in the unhealthy range, but still be healthy and have little risk of developing diabetes or having a heart attack.
  1. BMI also may not accurately reflect body fat in people who are very short (under 5 feet) or in older people who tend to lose muscle mass as they age. And, it may not be the best predictor of weight-related health problems among some racial and ethnic groups. For most people, BMI is a reliable way to tell if they are at an unhealthy weight.
  1. Excess weight, as measured by BMI, is not the only risk to your health -- so is the location of fat on your body. If you carry fat mainly around your waist, you are more likely to develop health problems than if you carry fat mainly on your hips and thighs. This applies even if your BMI is within the normal range.

  2. To measure your waist circumference, place a tape measure around your bare abdomen just above your hip bone. Be sure that the tape is snug, but do not compress your skin. Relax, exhale, and measure your waist. Women with a waist measurement of more than 35 inches or men with a waist measurement of more than 40 inches may have a higher disease risk than people with smaller waist measurements because of where their fat lies.
  3. Extra weight can put you at higher risk for developing these health problems:

    • type 2 diabetes (high blood sugar)
    • high blood pressure
    • heart disease and stroke
    • some types of cancer
    • sleep apnea (when breathing stops for short periods during sleep)
    • osteoarthritis
    • gallbladder disease
    • liver disease
    • irregular menstrual periods

    Talk to your health care provider about losing weight if your BMI is 30 or above, or your BMI is between 25 and 30 and you have two or more of the health problems listed above or a family history of heart disease or diabetes, or your waist measures over 35 inches (women) or 40 inches (men), even if your BMI is less than 25 and you have two or more of the health problems listed above or a family history of heart disease or diabetes.


    NIH Publication No. 04-5283, Weight and Waist Measurement: Tools for Adults

    Calculator Your Body Mass Index. NIH. Accessed 01/09/16.

    Calculate Body Maaa Index. February 13, 2013.

    Adult Obesity Facts. CDC. September 21, 2015.

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