Research
US Navy Method
Development, measurements and limitations of the historical U.S. Navy body fat equations.
6 sources
What the evidence says
Study scope
Hodgdon and Beckett evaluated their equations against underwater weighing in military samples.
Population limits
The original studies do not establish accuracy across all civilian or athletic populations.
Field assessment
Non-invasive measurements
Historical Development
Original Research (1984)
Hodgdon and Beckett developed separate equations for Navy men and women in the original reports listed below.
- Separate equations for men and women
- Based on circumference measurements and height
- Designed for field practicality
Method Evolution
- 1984: Original equations published
- June 2026 Navy guidance uses height, waist and weight for body composition assessment.
Method Details
Measurement Protocol
Male Measurements
- Standing height
- Neck circumference just below the larynx
- Waist circumference at the navel
Female Measurements
- Standing height
- Neck circumference just below the larynx
- Waist circumference at the narrowest abdominal level
- Hip circumference
Stand relaxed for circumference measurements. Both original reports specify a neck tape that slopes slightly downward toward the front.
Accuracy and limitations
Hodgdon and Beckett evaluated their equations against underwater weighing in military samples.
Those results do not establish a personal error bound for this calculator. Follow the reports’ measurement landmarks and tape placement.
Practical Applications
Historical military use
The original reports proposed the equations for Navy body fat assessment and weight-control decisions.
Harty and colleagues review military body composition standards and physical performance.
Research use
Schuna and colleagues compared the male circumference equation with air-displacement plethysmography in male Army ROTC cadets. It did not adequately detect body-composition changes following a small body-mass gain in that sample.
What this means for your measurement
Advantages and Limitations
Key Advantages
- Requires a tape measure and a way to measure standing height
- Non-invasive measurements
- The authors chose measurements intended for personnel with minimal training
Limitations
- The original studies do not establish accuracy across all civilian or athletic populations
- Posture and tape placement affect circumference readings