Your body mass index is your weight in relation to your height. In order to calculate your body mass index, just multiply your weight in pounds and divide it by the square of your height in inches. Having a body mass index greater than 23 will classify you as overweight, and a body mass index of over 30 will classify you as obese.
So is the body mass index really accurate? Although the calculation of BMI is an inexpensive way to determine a persons weight category, it should not be used as a diagnostic tool (To be a diagnostic tool, it should include measurements of body fat percentage, diet history, exercise patterns, and family history).
Not only should BMI not be used as a diagnostic tool, it does not take into account age gender or muscle mass (and it doesn’t differentiate between lean body mass and fat mass). Because of this, some people such as body builders or muscular athletes may have a high BMI even though they have a low percentage of body fat.
The national Heart, Lung and Blood institute recommends that all health care providers use BMI, waist circumference, and any other underlying factors that may contribute to obesity. Combining all of this information will provide you with the best assessment of your overall health and fitness.