Body fat by tape measurements
A tape measure and a height are enough for the Navy method. The sample is a woman at 5 ft 4 in with a 29 inch waist, a 38 inch hip and a 13 inch neck.
How it works
For females, body fat percent is 163.205 times the base 10 log of waist plus hip minus neck, minus 97.684 times the base 10 log of height, minus 78.387. All measures are in inches. For a woman the height on this page is 64 inches and the waist is 29 inches.
Worked example
Take a woman who is 5 ft 4 in tall with a 29 inch waist, a 38 inch hip and a 13 inch neck. Waist plus hip minus neck is 54 inches. The base 10 log of 54 is 1.73239. Multiply by 163.205: 1.73239 × 163.205 = 282.735. The base 10 log of 64 is 1.80618. Multiply by 97.684: 1.80618 × 97.684 = 176.435. Then 282.735 − 176.435 − 78.387 = 27.91. That is 27.9 percent body fat, in the average range.
Common questions
Can I enter centimeters?
Yes. Switch the units and the page converts everything to inches before it does the math. For a woman at 5 ft 4 in, a waist of 29 inches is 73.7 cm and a neck of 13 inches is 33.0 cm.
How accurate is the Navy method?
It is an estimate. It is usually within a few percentage points of more precise methods, and careful measuring matters. For a woman at 5 ft 4 in, a reading of 27.9 percent could be a few points higher or lower in practice.
Where do I place the tape?
Measure the neck just below the larynx. For men measure the waist at the navel. For women measure the waist at its narrowest point and the hips at their widest. Keep the tape snug and level without squeezing. For a woman at 5 ft 4 in the waist number is 29 inches and the neck number is 13 inches.
Does age change the result?
The formula does not use age. The same measurements give the same estimate at any age. A woman at 5 ft 4 in with a 29 inch waist, a 38 inch hip and a 13 inch neck gets 27.9 percent.
What is a healthy body fat percentage?
Ranges depend on sex and goals. The American Council on Exercise lists essential fat, athletes, fitness, average and obesity ranges. At 27.9 percent, a woman at 5 ft 4 in falls in the average range, which spans 25 to 31 percent.