Anyone seriously involved with sports is usually interested in how much of his total weight is broken down into fat versus lean muscle. There are a number of ways to calculate your percent body fat--including underwater weighing, bioelectrical impedance and skinfold measurements, to name a few. With the help of a friend and some inexpensive equipment, you can measure your own skinfolds and determine, with a relatively high degree of accuracy, your percent body fat.
Step 1
Understand that there are a number of different skinfold calipers available on the market--some fairly cheap and some very expensive. When purchasing skinfold calipers, you get what you pay for. For home use, you can buy them for as little as $10. The calipers used in professional laboratories and universities can cost several hundred dollars. The most important element in achieving accurate skinfold measurements is practice and the correct anatomical locations. Use the directions below, as well as the material accompanying the calipers you buy and practice.
Step 2
Take the following nine measurements, for men and women:
Bicep (vertical skin fold measurement on the bicep halfway between the shoulder and the forearm);
Triceps (vertical measurement right below where the triceps horseshoes);
Chest (vertical measurement at the top middle of the chest,below the collar bone;
Back (vertical pinch the skin between the scapula and spine;
Abdomen (vertical skin fold measurement to the right of the belly button;
Lower Back (horizontal measurement between the kidney and the spine;
Quadriceps (vertical measurement halfway up the quadriceps;
Calve (horizontal measurement at the top middle of the calve; and
Hip (horizontal measurement on the hip).
Step 3
Open and apply skinfold calipers to take a measurement. Take three measurements and average the three. Record the results on paper. Because you're measuring tissue that compresses, it takes a fair amount of expertise to arrive at consistent results, so be sure to take several measurements for each site and average the three. Even lab technicians who have performed thousands of skinfold measurements take multiple measurements and average them.
Step 4
Calculate a man's body fat. Assume that the total thicknesses of the nine skinfold sites is 96mm; divide them by the body weight of the subject (assuming a 190 pound male) = 0.505. Multiply the result by 0.28. The result would be 14 percent body fat:
96/190 = 0.505
0.505 * 0.28 = 0.14 (14 percent body fat)
Step 5
Measure the percent body fat for a woman. This is done in a similar manner as for men, with one exception: the calculation uses 0.30 instead of 0.28. To make the example simple, let's assume the same total skinfold measurements of 96mm and the same body weight. The equation would look like the following:
96/190 = 0.505
0.505 * 0.30 = 0.1515 (15.2 percent body fat)
Step 6
Try a number of different equations for estimating body fat from skinfolds by referencing the article, "Generalized equations for predicting body density of women." Medicine and Science in Sports and Exercise, 12, 175-182 (see Resources). There are also equation references for men.
Tips and Warnings
- There are as many different types of skinfold calipers as there are equations. Click on the link below for a complete selection of skinfold calipers. Try exploring several of them using the same test subject to determine which calipers offer the most accurate results.
- Do not hurry the measurements. Grip the skin firmly to avoid the calipers slipping.
Things You'll Need
- Skinfold calipers
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