- 1). Measure your height using a tape measure and jot it down on a piece of paper, making sure you convert feet into inches. You may need the assistance of another person to get an accurate measurement.
- 2). Weigh yourself on a standard scale and jot this number down in pounds on the same piece of paper as before.
- 3). Multiply your height in inches into itself. If you're 5 feet tall exactly, you would multiply 60 inches by 60 inches, giving you a number of 3,600.
- 4). Divide your weight (in pounds) by your multiplied height. If a 5-foot person weighed 120 pounds, she would take 120 and divide it by 3,600, getting a new number of 0.033.
- 5). Multiply this number by 703 to reach your body mass index (BMI). Using this calculation, the five-foot woman would have a BMI of 23.4, meaning she is of a normal weight.
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