How the US Navy Body Fat Formula Works
The US Navy circumference method is one of the most widely respected anthropometric equations in the world. Originally developed by researchers Hodgdon and Beckett at the Naval Health Research Center in 1984, it provides a standardized formula to evaluate body composition using simple circumference measurements.
US Navy Logarithmic Formulas
For Men:
% Body Fat = 495 / [1.0324 - 0.19077 × log₁₀(Waist - Neck) + 0.15456 × log₁₀(Height)] - 450
For Women:
% Body Fat = 495 / [1.29579 - 0.35004 × log₁₀(Waist + Hip - Neck) + 0.22100 × log₁₀(Height)] - 450
% Body Fat = 495 / [1.0324 - 0.19077 × log₁₀(Waist - Neck) + 0.15456 × log₁₀(Height)] - 450
For Women:
% Body Fat = 495 / [1.29579 - 0.35004 × log₁₀(Waist + Hip - Neck) + 0.22100 × log₁₀(Height)] - 450
*All circumference measurements must be calculated in centimeters.
How to Take Accurate Tape Measurements
- Neck: Measure around the neck just below the larynx (Adam's apple), keeping the tape level with shoulders relaxed.
- Waist (Men): Measure horizontally around the abdomen directly across the navel (belly button) at the end of normal exhalation. Do not suck in your stomach.
- Waist (Women): Measure at the natural narrowest circumference of the torso (typically halfway between the lowest rib and hip crest).
- Hips (Women): Measure around the widest horizontal circumference of the buttocks and hip bones.
Body Fat Percentage Categories (ACE Guidelines)
| Classification | Men (% Fat) | Women (% Fat) |
|---|---|---|
| Essential Fat | 2% – 5% | 10% – 13% |
| Athletes | 6% – 13% | 14% – 20% |
| Fitness | 14% – 17% | 21% – 24% |
| Average | 18% – 24% | 25% – 31% |
| Above Average (Obese) | 25%+ | 32%+ |
Frequently Asked Questions
Women naturally possess higher levels of essential fat (around 10–13% versus 2–5% in men) due to hormonal balances, childbearing physiological adaptations, and reproductive endocrine health.
Because body fat changes more slowly than daily water weight fluctuations, measuring once every 2 to 4 weeks under identical conditions (morning, fasted, post-urination) is recommended.