Estimate body-fat percentage with the U.S. Navy circumference method.
UNDERSTAND THE ANSWER
How is this calculated?
The circumference method estimates body composition from height plus neck and waist measurements; the female equation also uses hip circumference. It is a screening estimate, not a direct measurement.
U.S. Navy circumference estimateMale: 86.010 log₁₀(waist − neck) − 70.041 log₁₀(height) + 36.76
A practical example
For a 70-inch man with a 34-inch waist and 15-inch neck, the equation estimates body fat near 17.5%.
Assumptions, interpretation and common mistakes
Calculation assumptions
Circumferences and height are measured in inches.
The U.S. Navy circumference equations are used.
Measurements are taken consistently with a level tape that does not compress the skin.
How to interpret the result
The result is a screening estimate rather than a direct measurement of tissue.
Lean-mass share is simply 100% minus estimated body fat.
Repeated measurements are most useful when the same protocol and conditions are used.
Common mistakes to avoid
Mixing centimeters with inputs labeled in inches.
Pulling the tape too tightly or measuring at inconsistent locations.
Overreacting to small differences within normal measurement error.