How to Calculate BMI at Home

The BMI, or body mass index, of a person gives a general idea of how healthy the person is in a comparison of his weight and height. The higher the BMI, the more obese a person is. A low BMI, however, could signal that someone is underweight. To make the BMI calculation, you need your height and your weight. If your BMI is below 18.5, you are underweight. If your BMI is above 25, you are overweight.

Things You'll Need

• Scale
• Measuring stick

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Instructions

• 1

  Measure your height in inches. If you know your height in feet, multiply how many feet tall you are by 12 and then add any inches you are above the foot line. For example, suppose a person is 5 feet, 11 inches. First, multiply 5 by 12 to get 60. Then add 11 inches to have a total height of 71 inches.

• 2

  Measure your weight on a scale. In the example, the person weighs 180 lbs.

• 3

  Multiply your weight by 703. In the example, 180 times 703 equals 126,540.

• 4

  Square your height in inches. In the example, 71 squared equals 5,041.

• 5

  Divide the number calculated in Step 3 by the number calculated in Step 4 to calculate BMI. In the example, 126,540 divided by 5,041 equals 25.10216227.