An accurate estimate of your body fat requires you to make a few measurements of your body. You may then use these measurements to calculate the percentage of your body weight that comes from fat. Your body fat percentage is a common tool for assessing your progress in a fitness program. It takes your body composition into account, and is therefore a more accurate measure of your physical condition than your total weight.
Step 1
Take these body measurements whether you’re male or female. Measure your waist at the navel in inches with a tape measure. Weigh yourself in pounds with a bathroom scale. Make these measurements in the morning when your weight is at its lowest level.
Step 2
Make these measurements only if you’re female. Women must also measure their forearm, hips and wrist. Make these measurements at the widest points with a tape measure that uses inches.
Step 3
Compute your lean body weight if you’re male. The following formula provides the lean body weight for men: (weight x 1.082) - (waist x 4.15) + 94.42.
For example, let your waist measurement be 33 inches and let your weight be 171 lbs. You have a lean body weight of (171 x 1.082) - (33 x 4.15) + 94.42 = 142 lbs.
Step 4
Calculate your lean body weight if you’re female. The following equation provides the lean body weight for women: (weight x 0.732) - (waist x 0.157) + (forearm x 0.434) - (hips x 0.249) + (wrist / 3.14) + 8.987.
For example, let your waist measurement be 27 inches and let your weight be 131 lbs. Your forearm measures 10 inches, your hips measure 37 inches and your wrist measures 6.5 inches. You have a lean body weight of (131 x 0.732) - (27 x 0.157) + (10 x 0.434) - (37 x 0.249) + (6.5 / 3.14) + 8.987 = 98 lbs.
Step 5
Derive your body fat percentage from your lean body weight with the equation (total body weight - lean body weight) / (total body weight) x 100.
For example, let your total body weight be 171 lbs. and let your lean body weight be 142 lbs. You have a body fat percentage of (171 – 142) / (171) x 100 = 17 percent.
Things You'll Need
- Tape measure
- Bathroom scale
- Calculator
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