How to Calculate Male Body Fat

Directly measuring body fat is an expensive endeavor requiring high-tech laboratory equipment. Reliable approximations, however, can be made by calculating your body mass index, or BMI, and using a formula to convert this number to a body fat percentage. Drs. Deurenberg, Westrate and Seidell published this formula in the "British Journal of Nutrition" after establishing that it was as reliable as skinfold thickness measurements and bioelectrical impedance, two other commonly used indirect measurements for body fat.

Things You'll Need

• Scale
• Ruler or other flat, solid surface
• Measuring tape
• Calculator

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Instructions

• 1

  Step on the scale to find out how much you weigh in pounds. Write this number down on a piece of paper.

• 2

  Stand next to a wall. Place the ruler or other flat object on top of your head so that it touches the wall. Step away from the wall, leaving the ruler in place, and use a pencil to mark the place where the bottom of the ruler touches the wall.

• 3

  Use the measuring tape to determine the distance from the floor to the pencil mark on the wall. This is your height. Record your height in inches on the same sheet of paper as your weight.

• 4

  Calculate your BMI by dividing your weight by your height in inches squared and multiplying the quotient by 703. For example, if you weigh 175 lbs. and are 70 inches tall, you would divide 175 by 4900 to get the quotient .0357. Multiply this number by 703 to get 25.1, your BMI.

• 5

  Calculate your body fat percentage by using the following formula: (1.2 * BMI) + (.23 * age) - 15.4. For example, if your BMI is 25.1 and you are 35 years old, your body fat percentage would be 23.22.