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Clinical Body Composition

Body Fat Percentage Calculator

Measure body fat percentage, lean body mass, and essential fat stores using the Department of Defense U.S. Navy circumference model.

Navy Body Composition Engine

Real-time calculation • Dual US Imperial (in, lbs) / Metric (cm, kg)

Navy formula utilizes neck/waist for males and neck/waist/hip for females.
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Body Composition

U.S. Navy Standard
Estimated Body Fat Percentage
16.8%
Fitness Category
Total Fat Mass
28 lbs
Essential + storage adipose
Lean Body Mass
137 lbs
Muscle, bone, water, organs
American Council on Exercise (ACE) Norms:
  • Essential Fat: Men 2–5% | Women 10–13%
  • Athletes: Men 6–13% | Women 14–20%
  • Fitness: Men 14–17% | Women 21–24%
  • Average: Men 18–24% | Women 25–31%
  • Obese: Men ≥25% | Women ≥32%
Clinical Evidence & Methodology

The U.S. Navy Circumference Method & Hydrostatic Validation

Clinically Reviewed by Dr. Elena Rostova, PhD, RD • Updated September 2026

1. Mathematical Foundation of the Navy Method

Developed by Hodgdon and Beckett in 1984 at the Naval Health Research Center (San Diego, CA) for the U.S. Department of Defense (DoD Instruction 1308.3), this method estimates body fat percentage via logarithmic regression against hydrostatic underwater weighing. The formulas account for sex-specific adipose tissue deposition patterns (android abdominal fat in males vs. gynoid hip fat in females):

  • Men: %BF = 495 / [1.0324 - 0.19077 × log10(Waist - Neck) + 0.15456 × log10(Height)] - 450
  • Women: %BF = 495 / [1.29579 - 0.35004 × log10(Waist + Hip - Neck) + 0.22100 × log10(Height)] - 450

2. Accuracy Relative to Dual-Energy X-ray Absorptiometry (DEXA)

Validation studies demonstrate that the U.S. Navy method correlates strongly with DEXA (r = 0.85–0.90) with an average standard error of estimate (SEE) of 3.0–3.5%. It substantially outperforms bioelectrical impedance scales (BIA), which fluctuate drastically based on acute hydration status, recent sodium intake, and skin temperature.

3. Peer-Reviewed Citations

  1. Hodgdon, J. A., & Beckett, M. B. (1984). Prediction of percent body fat for US Navy men and women from body circumferences and height. Naval Health Research Center Reports, No. 84-29 and 84-11.
  2. Babcock, M. C., et al. (2020). Comparison of body composition assessment methods in young adults: dual-energy X-ray absorptiometry vs. anthropometric equations. Journal of Sports Sciences, 38(14), 1622-1629.
  3. American Council on Exercise (ACE). (2014). ACE Personal Trainer Manual (5th ed.). American Council on Exercise, San Diego, CA.
  4. Siri, W. E. (1961). Body composition from fluid spaces and density: analysis of methods. Techniques for Measuring Body Composition, 61, 223-244.