Whats Your Bmi - Are You Overweight: Obesity

Content provided by the Faculty of the Harvard Medical School

What's your BMI?

To calculate your BMI, follow these four steps:

1. Measure your height in inches (without shoes) and your weight in pounds (without clothing).

2. Multiply your weight by 703.

3. Divide that number by your height.

4. Divide again by your height.

You can also use a Web-based calculator at http://nhlbisupport.com/bmi or simply look up your BMI in Table 1. These categories were established after several studies examined the BMIs of millions of people and correlated them with rates of illness and death. The studies showed that the BMI range associated with the lowest rate of illness and death is approximately 19–25 in men and 18–25 in women, so people with BMIs in this healthiest range are considered to be of normal weight. Higher BMIs are associated with progressively higher rates of illness and death. People with BMIs of 25–30 are considered overweight, and those with BMIs of 30 or higher are considered to have obesity. Obesity has been further subdivided into mild (BMI of 30–35), moderate (35–40), and severe (BMI of 40 and above). Severe obesity is roughly equivalent to being 80 pounds overweight if you are a woman or 100 pounds if you are a man.

If your BMI is lower than 18, you are considered underweight. Underweight people also have higher death rates than people of normal weight do, but many people in this category are underweight because they already have a severe illness, such as cancer, chronic infections, or anorexia.

Last updated:	June 20, 2007