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Army Body Fat Calculator | US Army Circumference Method

An Army body fat calculator estimates body-fat percentage with the US Army circumference method from AR 600-9: log-transformed height, neck, waist (and hip for women) measurements. It outputs estimated body fat % and pass/fail against the Army's age- and sex-specific screening thresholds.

Last updated: September 2026 · Free · No sign-up required

Results

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Quick reference

Classic AR 600-9 max body fat (screening weight failure):

AgeMenWomen
17–2020%30%
21–2722%32%
28–3924%34%
40+26%36%

straighten Tape protocol

Three measurements each site, averaged: neck below the larynx, abdomen at the navel (men), natural waist and widest hip (women).

rule Log formula

The equation is log-based, so one inch off the waist−neck difference moves the result more than you'd expect — measure carefully.

military_tech Category limits

Allowed body fat rises with age band and category (e.g., recruiters and warrant officers have their own tables).

science Accuracy limits

±3–4% versus DEXA; muscular soldiers can fail the tape while being lean — the Army permits alternate assessments.

lightbulb A real example — male soldier, 175 cm

Height 69 in, neck 15 in, waist 34 in.

Result: %BF = 86.010×log(19) − 70.041×log(69) + 36.76 ≈ 18.6% — passes the ≤22% standard for age 21–27.

What this means: The waist−neck difference drives everything: dropping the waist 2 inches (same neck) takes this soldier to about 15.4%.

Formula & methodology

Formula: Men: %BF = 86.010×log10(waist−neck) − 70.041×log10(height) + 36.76 (inches)

The US Army tape test

AR 600-9's circumference method estimates body fat from three or four tape measurements (inches), validated against hydrostatic weighing in the 1980s DoD study:

  • Men: neck (below larynx), abdomen (at navel); %BF = 86.010×log(waist−neck) − 70.041×log(height) + 36.76.
  • Women: neck, natural waist (narrowest), hip (widest); %BF = 163.205×log(waist+hip−neck) − 97.684×log(height) − 78.387.

Standards (screening, under-40 in the classic table): men ≤ 20% (some categories 22–26%), women ≤ 30% (32–34% by category and age). Measure at end of a normal exhale, tape level, snug not compressing; take three readings and average.

The method runs ±3–4% versus DEXA — it can misclassify very muscular soldiers, which is why the Army moved to additional assessments.

Authoritative source: U.S. Army H2F

Frequently asked questions

How does the Army calculate body fat with a tape?
Log formulas from AR 600-9: men use height, neck and waist; women add hip circumference. The measurements are in inches, plugged into published log equations validated against underwater weighing.
What is the max body fat percentage in the Army?
It depends on age, sex and category — classically 20% (men) and 30% (women) at 17–20, rising to 26% / 36% at 40+.
How accurate is the tape test?
Within about ±3–4% of DEXA for most people, but it systematically overestimates fat in heavily muscled soldiers.
Where exactly do I measure neck and waist?
Neck just below the Adam's apple with tape sloping slightly down at the back; men's waist at the navel, women's at the natural narrowest point, hips at the widest — all after a normal exhale.

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