Health · Free tool
Body Fat % (US Navy)
The Navy circumference method: surprisingly accurate (±3% vs DEXA scan) and only needs a measuring tape — no skinfold callipers required.
Below the larynx, perpendicular to neck axis.
Men: at navel. Women: at narrowest point.
- Essential: 2-5% (men), 10-13% (women)
- Athletic: 6-13% / 14-20%
- Fitness: 14-17% / 21-24%
- Average: 18-24% / 25-31%
- Obese: 25%+ / 32%+
How it works
The US Navy formula (Hodgdon-Beckett, 1984) estimates body density from log-transformed circumferences, then converts to body-fat % via the Siri equation. For men: BF% = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. For women: hip is added. Validated against hydrostatic weighing on 600+ subjects with R² ≈ 0.90 and SEE ≈ 3.5%. Measure with a soft tape, no clothing over the waist, at end-expiration. Indian-origin adults often carry more visceral fat at the same BMI as Caucasians, so the WHO Asian cut-offs apply.
Worked example
A 32-year-old Bangalore software engineer, male, 175 cm tall: neck 38 cm, waist 88 cm. BF% ≈ 22% — borderline healthy/overweight for Indian-origin men (healthy <20%, athletic <15%). A 28-year-old female, 162 cm, neck 32 cm, waist 74 cm, hip 96 cm: BF% ≈ 28% — within the healthy female range (essential 10-13%, fitness 21-24%, average 25-31%).
When to use this
- Tracking fat-loss progress when BMI alone is misleading (high-muscle frames)
- Setting a calorie deficit using TDEE × deficit% on top of a fat-mass goal
- Confirming the “skinny-fat” pattern common in sedentary Indian IT workers
Pair this with our TDEE calculator and BMI calculator for a complete cut-or-bulk plan.
FAQ
How accurate is the Navy method?
Within ±3% of DEXA scan for most people. Less accurate for very lean or obese (extreme tails). Hydrostatic weighing and DEXA are gold-standard but require lab visits.
Where exactly do I measure?
Neck: just below larynx. Waist (men): at navel. Waist (women): narrowest point. Hip (women): widest point of buttocks. Stand relaxed, exhale normally.
Why no skinfold method?
Skinfolds need callipers and a trained measurer. Navy method only needs a tape. For at-home self-measurement, Navy is the most reliable.