Body fat for males aged 20 to 29
A tape measure and a height are enough for the Navy method. The sample is a man in his 20s at 5 ft 10 in with a 33 inch waist and a 15 inch neck.
How it works
The male Navy formula takes the waist minus the neck in inches and finds its base 10 log. Multiply that by 86.010. Then subtract 70.041 times the base 10 log of height and add 36.76. For a man in his 20s at 70 inches, waist minus neck is 18 inches.
Worked example
A man in his 20s who is 5 ft 10 in tall has a 33 inch waist and a 15 inch neck. Waist minus neck is 18 inches. The base 10 log of 18 is 1.25527, and 1.25527 × 86.01 = 107.966. The base 10 log of 70 is 1.84510, and 1.84510 × 70.041 = 129.233. 107.966 − 129.233 + 36.76 = 15.49, which rounds to 15.5 percent. That is in the fitness range.
Common questions
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 man in his 20s at 5 ft 10 in the waist number is 33 inches and the neck number is 15 inches.
Does age change the result?
The formula does not use age. The same measurements give the same estimate at any age. A man in his 20s at 5 ft 10 in with a 33 inch waist and a 15 inch neck gets 15.5 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 15.5 percent, a man in his 20s 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 in his 20s, a waist of 33 inches against a height of 70 inches gives a waist-to-height ratio of 0.47.
Can I enter centimeters?
Yes. Switch the units and the page converts everything to inches before it does the math. For a man in his 20s at 5 ft 10 in, a waist of 33 inches is 83.8 cm and a neck of 15 inches is 38.1 cm.