Calculating % Bodyfat - Girth Method
Body fat is only one part of the composition of the human body, and it is particularly important to monitor the fat levels for health and for athletes. There are many ways of estimating the body's fat percentage. The methods described below are calculations based on simple girth or circumference measurements. See the information about %body fat, and also using skinfold measures to calculate %bodyfat.
BF% from Girth Measurements
Here are some formula for the estimation of body fat using body circumference measurements (Katch & McArdle, 1983). All circumference measurements are in inches. The values in [square brackets] are used if the individual participates in more than 240 minutes of vigorous activity per week.
- Younger Women (17-26 years): % body fat = (abdominal x 1.34) + (thigh x 2.08) – (forearm x 4.31) – 19.6 [or 22.6]
- Older Women (over 26 years): % body fat = (abdominal x 1.19) + (thigh x 1.24) – (calf x 1.45) – 18.4 [or 21.4]
- Younger Men (17-26 years): % body fat = (upper arm x 3.70) + (abdominal x 1.31) – (forearm x 5.43) – 10.2 [or 14.2]
- Older Men (over 26 years): % body fat = (buttock x 1.05) + (abdominal x 0.90) – (forearm x 3.00) – 15.0 [or 19.0]
Formulas from the US Department of Defense
There are formula from the US Department of Defense to compute body-fat percentage using girth measurements and height. There are different formula for males and females. The males require girth measures of the neck and abdominal girth. The females require girths of the neck, waist and hip. You will need a scientific calculator to determine the log calculations.
Using Imperial Units (inches)
This is the formula (Hodgdon and Beckett, 1984) that was taken from the Navy website, and is seen elsewhere on the internet. Note, all measurements are in inches (measured to the nearest 1/4 inch), including height.
- males: % body fat = 86.010 x log10(abdomen - neck) - 70.041 x log10(height) + 36.76
- females: % body fat = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387
Using Metric Measurements (cm)
This is believed to be the metric version of the Navy body fat formula. Note, all measurements are in centimeters to the nearest 0.5 cm, including height.
- males: % body fat = 495/(1.0324-0.19077(log(waist-neck))+0.15456(log(height)))-450
- females: % body fat = 495/(1.29579-0.35004(log(waist+hip-neck))+0.22100(log(height)))-450
This is another formula found online, but there was no mention of the original source. For the females, there are additional measurements needed compared to the formula above.
- males: % body fat = (76.5 * LOG10((abdomen) - (neck))) - (68.7 * LOG10(height)) + 46.9
- females: % body fat = (105.3 * LOG10(weight)) - (0.200 * (wrist)) - (0.533 * (neck)) - (1.574 * (forearm)) + (0.173 * (hip)) - (0.515 * (height)) - 35.6
- Hodgdon, J.A. and M.B. Beckett (1984) Prediction of percent body fat for U.S. Navy men from body circumferences and height. Report no. 84-11, Naval Health Research Center, San Diego, CA;
- Hodgdon, J.A. and M.B. Beckett (1984) Prediction of percent body fat for U.S. Navy women from body circumferences and height. Report no. 84-29, Naval Health Research Center, San Diego, CA.
- Katch, F.I., McArdle, W.D., Nutrition, Weight Control, and Exercise. Lea & Febiger: Philadelphia. PA, 1983.