US Navy body fat calculator
A tape measure and a height are enough for the Navy method. The sample is a man at 5 ft 10 in with a 34 inch waist and a 15.5 inch neck.
How it works
For males, body fat percent is 86.010 times the base 10 log of waist minus neck, minus 70.041 times the base 10 log of height, plus 36.76. All measures are in inches. The neck on this male page is 15.5 inches and the height is 70 inches.
Worked example
Take a man who is 5 ft 10 in tall with a 34 inch waist and a 15.5 inch neck. Waist minus neck is 18.5 inches. The base 10 log of 18.5 is 1.26717. Multiply by 86.01: 1.26717 × 86.01 = 108.989. The base 10 log of 70 is 1.84510. Multiply by 70.041: 1.84510 × 70.041 = 129.233. Then 108.989 − 129.233 + 36.76 = 16.52. That is 16.5 percent body fat, in the fitness range.
Common questions
Does age change the result?
The formula does not use age. The same measurements give the same estimate at any age. A man at 5 ft 10 in with a 34 inch waist and a 15.5 inch neck gets 16.5 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 16.5 percent, a man at 5 ft 10 in falls in the fitness range, which spans 14 to 17 percent.
Why does the waist matter more than weight?
Waist size reflects fat carried around the middle, while body weight cannot tell fat from muscle. For a man, a waist of 34 inches against a height of 70 inches gives a waist-to-height ratio of 0.49.
Can I enter centimeters?
Yes. Switch the units and the page converts everything to inches before it does the math. For a man at 5 ft 10 in, a waist of 34 inches is 86.4 cm and a neck of 15.5 inches is 39.4 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 man at 5 ft 10 in, a reading of 16.5 percent could be a few points higher or lower in practice.