Body Mass Index, or BMI, is a calculation obtained by a person’s height and weight. While your doctor or fitness trainer may have a handy calculator to feed the numbers into for instant results, it may be helpful at home to learn to do this fairly straightforward equation. Tracking your BMI is an excellent tool to use in estimating your body fat and setting goals in your weight loss program.
Measure your height in inches and weight in pounds without shoes or heavy clothing. For this example, we’ll calculate Body Mass Index using pounds and inches for a woman who is 5 feet 2 inches and weighs 125 lbs. Both systems use the same formula: Divide weight by height squared and multiply by 703.
Calculate the square of your height in inches by multiplying the number by itself: 5 feet 2 inches equals 63 inches; 63 times 63 equals 3,969.
Divide your weight by the squared height: 125 divided by 3,969 equals .03149.
Multiply the resulting number by the conversion factor of 703: .03149 times 703 equals 22.14. This is your BMI.
Determine your Body Mass Index status by using the following figures. Below 18.5 is considered underweight. A BMI between 18.5 and 24.9 is considered to be in the normal range. A BMI of 25.0 to 29.9 is considered to be in the overweight range, and 30.0 and above is considered obese.
- Remember that your BMI is only one aspect of your overall health. Your waist measurement and physical inactivity are other important factors to consider.