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Estimate body-fat percentage from measurements using the US Navy circumference method (DoDI 1308.3).
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Estimates body-fat percentage from neck, waist, (and hip for women) circumference measurements using the US Navy method, plus the ACE body-fat category.
BMI ignores body composition. The US Navy circumference method (Hodgdon & Beckett, standardized in DoD Instruction 1308.3) is the best-validated tape-measure estimate — within roughly ±3–4% of DEXA for most people and requiring only a tape measure.
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Fitness enthusiasts tracking composition, service members prepping for official tape tests, and trainers monitoring client progress.
Choose sex and measurement unit
Measure height, neck, and waist snug (not tight); women also measure hip at the widest point
Waist: men measure at the navel; women at the narrowest point
Read the estimated body-fat % and its ACE category
Male, 70in, neck 16in, waist 36in → ≈ 20% (Average)Female, 65in, neck 13in, waist 28in, hip 39in → ≈ 26% (Average)Same numbers in cm work identically after conversionQ: How accurate is the Navy method?
A: Roughly ±3–4% versus DEXA for most adults; it degrades at extremes of muscularity or obesity.
Q: Which category bands does it use?
A: The American Council on Exercise (ACE) chart: Essential / Athletes / Fitness / Average / Obese.
Q: Does it work for children? A: No
the coefficients are adult-calibrated.
Q: My smart scale disagrees with this result. Which is right?
A: Neither is clinical-grade; use whichever tracks most consistently for you.
Authoritative specifications, standards, and in-depth reading for Body Fat Calculator (US Navy).
Estimated body fat
19.4%
ACE category: Average
US Navy circumference method (DoDI 1308.3). Estimates ±3–4% vs DEXA. Measure snug, not tight; waist at navel (men) or narrowest point (women). Not medical advice. Runs locally.
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