Army Body Fat Calculator

This Army body fat calculator estimates body fat percentage from height, neck, waist, and — for the female equation — hip measurements using the AR 600-9 circumference method. It then shows the age-band screening-table maxima from the regulation as reference information. The calculator makes no pass or fail determination: the screening tables are policy-bound, and the page is educational.

Measurements

The calculator asks for:

• Gender — selects which AR 600-9 equation applies.
• Age — selects the reference age band only (the equations themselves do not use age).
• Height in inches — measured without shoes, to the nearest half inch.
• Neck in inches — measured just below the larynx, perpendicular to the long axis of the neck.
• Waist in inches — for males, the abdomen measured at navel level; for females, the natural waist at its smallest point. Measured at the end of a normal relaxed exhalation.
• Hip in inches — for the female equation only, measured over the greatest protrusion of the gluteal muscles.

All circumference measurements follow the AR 600-9 half-inch rounding conventions.

Formula

For a male entry, the coded body fat equation is (all measurements in inches):

$\text{body fat raw} = 86.010 \times \log_{10}(\text{waist} - \text{neck}) - 70.041 \times \log_{10}(\text{height}) + 36.76$

For a female entry:

$\text{body fat raw} = 163.205 \times \log_{10}(\text{waist} + \text{hip} - \text{neck}) - 97.684 \times \log_{10}(\text{height}) - 78.387$

The displayed body fat percentage is:

$\text{body fat percentage} = \operatorname{round}(\text{body fat raw})$

per the regulation’s “round to the nearest whole percent” instruction. Use base-10 logarithms: entering a natural log (ln) instead of log10 changes the result substantially.

Worked example

Suppose the entry is male, age 25, height 72 inches, neck 15 inches, and waist (abdomen) 34 inches. The male equation gives:

$\text{waist} - \text{neck} = 34 - 15 = 19$

$\log_{10}(19) = 1.278753601, \quad \log_{10}(72) = 1.857332496$

$\text{body fat raw} = 86.010 \times 1.278753601 - 70.041 \times 1.857332496 + 36.76 = 16.66$

The calculator rounds 16.66 to 17 percent. Age 25 falls in the 21 through 27 male band, so the page shows the AR 600-9 Table B-2 reference maximum for that band (male 22 percent, female 32 percent) — as reference only, with no pass or fail verdict.

Age-band screening tables (reference only)

The maximum allowable percent body fat standards from AR 600-9, Table B-2, are shown for reference and are not used to pass or fail your entry:

These limits are policy-bound: official determinations depend on the current Army Body Composition Program, trained personnel, the required measurement and rounding procedures, and the prescribed forms (DA Form 5500 for males, DA Form 5501 for females). This calculator deliberately emits no pass or fail verdict.

Interpreting the result

The percentage is only an estimate produced by this calculator. Official Army standards are governed by the Army Body Composition Program and policy documents such as AR 600-9. In practice, the measurement environment matters: tape placement, tape tension, posture, rounding rules, repeated measurements, and who performs the measurement can affect the recorded value. A one-inch waist difference changes the male formula by 86.010 × (log10(waist − neck) − log10(waist − neck − 1)) percentage points before rounding and the female formula by a similar log-scale amount, so small measurement errors can move a result.

The circumference equations estimate body fat from body-size patterns; they do not measure fat directly like a laboratory method. They also do not account for body water, muscularity, or fat distribution. Two people with the same measurements can have different body compositions. Treat the output as a transparent calculation of the current page, not a complete assessment of health, readiness, or performance.

For other body-composition screens, pair this estimate with the BMI calculator, the legacy circumference body fat estimate, and the A Body Shape Index calculator, which combines waist, height, and weight.

Limitations and disclaimer

This calculator is educational only and is not medical advice. It does not diagnose obesity, evaluate metabolic risk, prescribe weight loss, or recommend training. It also does not make official military determinations or pass or fail anyone against Army standards. For medical questions, consult a qualified healthcare professional. For Army compliance, use the current Army Body Composition Program materials and the chain of command or authorized personnel.

Common mistakes

• Using the natural log (ln) instead of log10 — the equations require base-10 logarithms.
• Forgetting that the male waist is the abdomen at navel level, not the trouser waist.
• Forgetting the hip measurement for the female equation (the calculator hides it for males).
• Measuring height in feet and inches and entering it as a single number — enter total inches.
• Reading the reference screening maxima as a pass or fail verdict — this page does not make that determination.
• Treating the estimate as an official Army body fat determination rather than an educational calculation.

Sources

• U.S. Army Publishing Directorate, AR 600-9: The Army Body Composition Program (16 July 2019 edition, archived PDF) — Appendix B, Table B-5 gives the circumference equations this page implements and the “round to the nearest whole percent” rule; Table B-2 gives the age-band screening-table maxima shown as reference. armypubs no longer serves this PDF directly; the snapshot was archived 2024-11-06.
• U.S. Army Publishing Directorate, AR 600-9 publication record (armypubs.army.mil) — confirms the 16 July 2019 edition is the active AR 600-9 and that the program prescribes DA Form 5500/5501 body-fat worksheets.
• CDC, About Body Mass Index — explains BMI as a screening measure rather than a direct body-fat measurement.
• NIH Office of Dietary Supplements, Dietary Supplements for Exercise and Athletic Performance — background on performance claims and the need for evidence-based health decisions.