Estimate body fat percentage using the same circumference (tape test) method used by the US Army for fitness standards.
The Army body fat method estimates body fat percentage purely from circumference measurements — no calipers required. Men need neck, waist and height; women additionally need a hip measurement. It's a log-based formula developed to standardize military fitness testing across a large population.
Enter values to see your results.
%BF = 86.010 × log10(Waist − Neck) − 70.041 × log10(Height) + 36.76
%BF = 163.205 × log10(Waist + Hip − Neck) − 97.684 × log10(Height) − 78.387
All measurements in inches (this calculator converts cm automatically)
Neck: below larynx. Waist: at navel. Hip: widest point (women only).
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Unlike skinfold testing, this method needs only a flexible tape measure and a height reading.
This is an estimate for general fitness tracking; official military body-composition assessments follow strict, standardized protocols.
The Army method sidesteps calipers entirely, using log-transformed circumference differences to approximate body fat.
Estimate standing relative to service body-composition standards.
Track progress ahead of official assessments.
Similar tape-test standards are used in some academy fitness requirements.
Track body fat trend without owning calipers or a DEXA scan.
Trainers can estimate client body fat with just a tape measure.
A consistent, repeatable number to pair with progress photos.
Height 70in, neck 15in, waist 34in → body fat ≈ 15.6% (Fitness category).
Height 64in, neck 12in, waist 28in, hip 38in → body fat ≈ 23.6% (Fitness category).
Male, height 70in, neck 15in, waist 40in → body fat ≈ 24.9% (borderline Average/Obese).
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