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Navy Body Fat Calculator — Circumference Method

Estimate body fat using the US Navy circumference method (neck, waist, height, plus hip for women). Instant %BF with fitness category.

Updated
Estimated Body Fat (Navy Circumference Method)
15.5%

Category: Fitness

Measurement Tips

Neck: just below the larynx (Adam's apple), tape sloped slightly downward toward the front. Waist: the narrowest point of the torso, usually just above the navel — not compressed. Height: without shoes, standing fully upright.

US Navy circumference formula (Hodgdon & Beckett, Naval Health Research Center, 1984). Male: 86.010×log₁₀(waist−neck) − 70.041×log₁₀(height) + 36.76. Female: 163.205×log₁₀(waist+hip−neck) − 97.684×log₁₀(height) − 78.387. All measurements in inches (values entered in centimeters are converted automatically). This is an estimate for reference only — it is less precise than DEXA scans or hydrostatic (underwater) weighing, and the Navy's own current pass/fail Body Composition Assessment standards are set separately by age bracket in the official instruction, not by this general-population category table.
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Reference Values

Last verified:
Category Range What It Means Status
Male — Essential Fat 2–5% The minimum fat needed for basic physiological health. Not a target range — going this low outside of competitive bodybuilding prep can affect hormone and immune function. Okay
Male — Athletes ★ 6–13% Typical range for competitive athletes and highly trained individuals. ★ Best
Male — Fitness 14–17% Lean, visibly fit range for regularly active men — the most common sustainable target. Good
Male — Acceptable 18–24% Average, healthy range for the general male population. Okay
Male — Obese 25%+ Associated with elevated health risk; the Navy's own operational maximum-allowed standards (by age bracket) fall within or below the top of this range. Poor
Female — Essential Fat 10–13% The minimum fat needed for basic physiological health, including reproductive function. Not a target range for most women. Okay
Female — Athletes ★ 14–20% Typical range for competitive female athletes and highly trained individuals. ★ Best
Female — Fitness 21–24% Lean, visibly fit range for regularly active women — the most common sustainable target. Good
Female — Acceptable 25–31% Average, healthy range for the general female population. Okay
Female — Obese 32%+ Associated with elevated health risk. Poor

Source: Body fat percentage categories: American Council on Exercise (ACE) body composition classification, the standard civilian reference for interpreting circumference-method body fat results. The underlying %BF formula is the Hodgdon & Beckett (Naval Health Research Center, 1984) circumference-based equation — the original 'Navy method' still used across most circumference body-fat calculators today. The Navy's own current operational Body Composition Assessment (OPNAVINST 6110-series) uses graduated maximum-allowed body fat percentages by age bracket for pass/fail purposes, which are updated periodically — sailors should confirm the current standard against the latest instruction rather than this general-population table.

Worked Examples

Male, Athletic Build

Sex
Male
Waist
32 in
Neck
15 in
Height
72 in
12.5% body fat

86.010×log₁₀(32−15) − 70.041×log₁₀(72) + 36.76 = 86.010×1.2304 − 70.041×1.8573 + 36.76 = 12.50%. Falls in the 'Athletes' category (6–13%).

Male, Fitness Range

Sex
Male
Waist
34 in
Neck
16 in
Height
70 in
15.5% body fat

86.010×log₁₀(34−16) − 70.041×log₁₀(70) + 36.76 = 15.49%. Falls in the 'Fitness' category (14–17%) — a common sustainable target for active men.

Female, Athletic Build

Sex
Female
Waist
26 in
Hip
34 in
Neck
12 in
Height
64 in
19.6% body fat

163.205×log₁₀(26+34−12) − 97.684×log₁₀(64) − 78.387 = 19.57%. Falls in the 'Athletes' category (14–20%).

Female, Acceptable Range

Sex
Female
Waist
30 in
Hip
38 in
Neck
13 in
Height
64 in
29.2% body fat

163.205×log₁₀(30+38−13) − 97.684×log₁₀(64) − 78.387 = 29.21%. Falls in the 'Acceptable' category (25–31%) for the general female population.

Male, Above Acceptable Range

Sex
Male
Waist
42 in
Neck
17 in
Height
68 in
28.6% body fat

86.010×log₁₀(42−17) − 70.041×log₁₀(68) + 36.76 = 28.65%. Falls in the 'Obese' category (25%+) — above the Navy's own operational maximum-allowed standards at any age.

How to Use This Calculator

  1. 1

    Select your sex

    Male or female — the formula and required measurements differ (the female formula adds a hip measurement).

  2. 2

    Choose your unit

    Inches or centimeters. Centimeter entries are converted to inches automatically since that's the formula's native unit.

  3. 3

    Enter your neck and waist measurements

    Neck just below the larynx; waist at its narrowest point above the navel.

  4. 4

    Enter hip measurement (women) and height

    Hip at the widest point around the buttocks; height measured without shoes.

  5. 5

    Read your estimated body fat percentage and category

    Compares your result against the standard Essential Fat / Athletes / Fitness / Acceptable / Obese categories for your sex.

What Each Value Means

Navy Body Fat % (% body fat)
Estimated body fat percentage calculated from neck, waist, height, and (for women) hip circumference measurements, using the Hodgdon & Beckett Naval Health Research Center formula.
Fitness Category (category)
Where your estimated body fat percentage falls among five standard classification bands — Essential Fat, Athletes, Fitness, Acceptable, and Obese — commonly used to interpret circumference-method body fat results.

Related Calculators

Frequently Asked Questions

What is the US Navy body fat formula?
It's a circumference-based equation developed by Hodgdon and Beckett at the Naval Health Research Center in 1984. For men: %BF = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. For women: %BF = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387. All measurements are in inches, and the formula uses base-10 logarithms.
Why does the female formula need a hip measurement but the male formula doesn't?
The original research found that adding hip circumference meaningfully improved prediction accuracy for women but not for men, because body fat distribution patterns differ by sex — women tend to store more fat around the hips and thighs, which the waist-and-neck-only formula doesn't capture well. Men's fat distribution is predicted accurately enough using just waist and neck.
How is this different from the Army body fat calculator on this site?
Both are circumference-method formulas, but they use different coefficients and, as of 2024, different measurement sites. The Army's current official method uses only weight and abdominal (navel) circumference in a linear formula. The Navy method used here is the older log-based formula measuring neck, waist, height, and (for women) hip — it's also the formula most civilian body-fat calculators and fitness trackers use, since it was published as general circumference-method research rather than tied to one branch's current test administration.
How accurate is the Navy body fat formula compared to DEXA or hydrostatic weighing?
It's a reasonable field estimate but noticeably less precise than lab methods like DEXA (dual-energy X-ray absorptiometry) or hydrostatic (underwater) weighing, which directly measure tissue density and composition. Circumference formulas can be off by several percentage points for people with atypical fat distribution or very high or low muscle mass. Use this calculator to track trends over time rather than as a precise diagnostic number.
Where exactly should I measure my waist and neck for this calculator?
Measure your neck just below the larynx (Adam's apple), with the tape sloped slightly downward toward the front of the neck. Measure your waist at its narrowest point, usually just above the navel, with the tape snug against the skin but not compressing it — don't suck in your stomach. For women, measure hip circumference at the widest point around the buttocks.

References & Sources

  1. [1]
    MyNavyHR — Guide 4: Body Composition Assessment (BCA) (opens in new tab)

    Supports: Evidence used for body composition measurement methods glossary, including related formulas, definitions, or reference values.

    Verified

  2. [2]
    MyNavyHR — Physical Readiness Program (opens in new tab)

    Supports: Evidence used for body composition measurement methods glossary, including related formulas, definitions, or reference values.

    Verified