How to Calculate Someone's BMI

BMI, or body-mass index, is a quick formula that estimates whether you are underweight, average, overweight or obese based on your height and weight. According to the National Heart, Lung, and Blood Institute, the same formula for BMI is used for both men and women. However, the Centers for Disease Control advises that women will have a higher body-fat percentage than men with the same BMI level. Generally, a BMI between 18.5 and 24.9 is considered "normal."

Things You'll Need

• Calculator

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Instructions

• 1

  Convert your height in feet and inches to inches by multiplying the feet by 12 and adding the number of inches. For example, if you are 6 feet 2 inches tall, you would multiply six by 12 to get 70 and add two to get 72.

• 2

  Square your height in inches. In this example, you would square 72 to get 5,184.

• 3

  Divide your weight in pounds by the result from step 2. In this example, if your weight equals 190, you would divide 190 by 5,184 to get 0.03665.

• 4

  Multiply the result from step 3 by 703 to find your BMI. Finishing the example, you would multiply 0.03665 by 703 to find the BMI equals 25.76.