How does the US Army calculate body fat?

The US Army uses the circumference-based method (AR 600-9): For men: %BF = 86.010 × log(waist − neck) − 70.041 × log(height) + 36.76. For women: %BF = 163.205 × log(waist + hip − neck) − 97.684 × log(height) − 78.387. Measurements are in inches. This method was developed by Hodgdon and Beckett (1984) at the Naval Health Research Center. Accuracy is ±3–4% compared to hydrostatic weighing.

What are the US Army body fat standards?

US Army body fat limits (AR 600-9) by age: Men: 17–20 years ≤20%, 21–27 years ≤22%, 28–39 years ≤24%, 40+ years ≤26%. Women: 17–20 years ≤30%, 21–27 years ≤32%, 28–39 years ≤34%, 40+ years ≤36%. Soldiers exceeding these limits enter a weight control program.

How do UK, Australian, and Canadian military standards compare to the US?

UK Army does not use circumference-based body fat; instead uses BMI (18.5–32 range) and a fitness test (APFA). Australian Defence Force uses a 'waist-to-height ratio' target of below 0.5 for most roles, plus fitness testing. Canada uses BMI (17–33) plus fitness standards. Japan's Self-Defense Forces use BMI plus physical fitness tests. The US Army's circumference method is one of the few militaries using this specific technique.

🇺🇸 US Army AR 600-9 🇬🇧 British Army 🇦🇺 ADF Australia 🇨🇦 Canadian Forces

Army Body Fat Calculator

Calculate body fat percentage using the US Army circumference method (AR 600-9). This tape measurement method is used by the US Army, Navy, Marine Corps, and Coast Guard — and compares differently to how the UK, Australia, and Canada assess military fitness.

Quick Answer

US Army uses waist, neck (and hip for women) measurements to calculate body fat %. Limits: men ≤20–26% (age-dependent); women ≤30–36%. UK Army uses BMI + fitness test, not body fat %. Australia uses waist-to-height ratio. Canada uses BMI. The US method (Hodgdon & Beckett, 1984) is one of the only militaries using circumference-based body fat calculation.

Sex

Height (cm)

Neck circumference (cm)

Below the larynx

Waist circumference (cm)

At narrowest point

Military Body Composition Standards by Country

Military	Method	Standard
🇺🇸 US Army (AR 600-9)	Circumference method (waist, neck, hip)	Men ≤20–26%, Women ≤30–36% (age-dependent)
🇺🇸 US Navy / USMC	Same circumference method	Similar to Army with branch-specific limits
🇬🇧 British Army	BMI + fitness test (APFA)	BMI 18.5–32; no body fat % standard
🇦🇺 Australian ADF	Waist-to-height ratio + fitness test	Waist-to-height < 0.5 for most roles
🇨🇦 Canadian Armed Forces	BMI (17–33) + fitness test (EXPRES)	BMI range + Physical Fitness Test
🇩🇪 German Bundeswehr	BMI + annual fitness test	BMI 18–30; fitness test by service branch
🇯🇵 Japan Self-Defense	BMI + physical fitness test	BMI 17.5–25 for new recruits

Frequently Asked Questions

How do I measure neck circumference for the Army body fat test? ▾

Measure neck circumference just below the larynx (Adam's apple), keeping the tape horizontal and close to the skin but not compressing it. For men: the measurement is taken at the narrowest point of the neck, just below the larynx. For women: measure at the mid-neck, below the larynx. Round measurements down to the nearest 0.5 inch (or 1 cm). Consistent measurement technique significantly affects accuracy.

How accurate is the Army circumference method? ▾

The US Army circumference method (Hodgdon & Beckett, 1984) has a standard error of approximately ±3–4% body fat when compared to hydrostatic weighing. It systematically underestimates body fat in muscular individuals and may overestimate in individuals with different fat distribution patterns. The US Army has used this method since the 1980s because it requires only a tape measure, is fast to administer, and can be applied in field conditions worldwide.