US Army standard circumference method — measurements in any unit.
Male: %BF = 86.010 × log₁₀(abdomen − neck) − 70.041 × log₁₀(height) + 36.76 | Female: %BF = 163.205 × log₁₀(hip + waist − neck) − 97.684 × log₁₀(height) − 78.387
The Army uses logarithm-based circumference equations developed by Hodgdon and Beckett (1984) and adopted in Army Regulation 600-9. Separate formulas apply to males and females. All measurements are in inches.
Male formula:
%BF = 86.010 × log10(abdomen − neck) − 70.041 × log10(height) + 36.76
Female formula:
%BF = 163.205 × log10(hip + waist − neck) − 97.684 × log10(height) − 78.387
Results are rounded to the nearest whole percent per Army regulation.
%BF = 86.010 × log₁₀(34.0 − 15.5) − 70.041 × log₁₀(70) + 36.76 = 86.010 × log₁₀(18.5) − 70.041 × log₁₀(70) + 36.76 = 86.010 × 1.2672 − 70.041 × 1.8451 + 36.76 = 108.99 − 129.23 + 36.76 = 16.52 → rounded to 17%
Result: Estimated Body Fat: **17%**
A result of 17% body fat places this male soldier within the acceptable range for all Army age groups (the Army standard for males ranges from 20% to 26% depending on age bracket under AR 600-9). A lower number is generally better; if your result exceeds the standard for your age group, you would be flagged for the Army Body Composition Program (ABCP). Always verify measurements are taken correctly — tape placement errors are the most common source of inaccurate readings.
⚠️ Disclaimer: This calculator is provided for educational and informational purposes only. It is not medical advice, a clinical body fat assessment, or an official Army determination. For official Army body composition screening, measurements must be taken by a trained Army personnel administrator following AR 600-9 protocols.
The U.S. Army Body Composition Program (ABCP), governed by Army Regulation 600-9, uses a circumference-based tape test rather than hydrostatic weighing or DEXA scans because it is fast, inexpensive, and can be administered anywhere in the field.
The tape test estimates the distribution of body fat using the relationship between limb and torso circumferences and total body fat, a method validated by Hodgdon and Beckett at the Naval Health Research Center. While it is less precise than laboratory methods (typical error ±3–4 percentage points), it is consistent and standardized across the entire Army.
Standards are split by gender and age group. Generally:
| Age Group | Male Maximum | Female Maximum | |-----------|-------------|----------------| | 17–20 | 20% | 30% | | 21–27 | 22% | 32% | | 28–39 | 24% | 34% | | 40+ | 26% | 36% |
These standards apply at the time of enlistment and throughout a soldier's career. Soldiers who exceed the standard are enrolled in the Army Body Composition Program (ABCP) and given 6 months to comply.
The tape test is only administered if a soldier first fails the height-and-weight screening tables in AR 600-9. Not every soldier is taped at every weigh-in — only those who exceed the screening weight for their height.
Reducing waist circumference (males) and waist + hip circumference (females) while maintaining neck size will lower your tape-test score. Targeted resistance training that builds neck musculature alongside cardiovascular exercise for fat loss is the most effective dual strategy.
Under AR 600-9, the maximum allowed body fat ranges from 20–26% for males and 30–36% for females, depending on age group. The oldest group (40+) has the most lenient standards.
Focus on reducing waist (and hip for females) circumference through cardiovascular exercise and calorie management, while maintaining or increasing neck circumference through resistance training. The formula rewards a smaller waist-to-neck ratio.
They are similar but use slightly different formula constants. The Navy/Marine Corps tape test uses the same Hodgdon-Beckett methodology but with constants calibrated for their specific populations and may have different circumference measurement sites.
Yes — a larger neck circumference (from muscle development) reduces the calculated body fat percentage in the formula, because the formula subtracts neck from abdomen. Muscular soldiers with large necks often score more favorably than their actual fat percentage might suggest.
Under AR 600-9, official height and weight measurements occur at least semi-annually. Soldiers who exceed the weight screening table are taped at that time. Soldiers in the ABCP may be measured monthly.
No — it estimates body fat percentage using a mathematical model based on body circumferences. It correlates reasonably with actual body fat but has a margin of error of roughly ±3–4 percentage points compared to laboratory methods like DEXA or hydrostatic weighing.
Soldiers who exceed AR 600-9 body fat standards are enrolled in the Army Body Composition Program (ABCP). They receive nutrition counseling and a fitness plan and are re-evaluated monthly. Failure to meet the standard within 6 months can result in separation from the Army.
Yes. The male formula uses only abdomen and neck circumferences, while the female formula incorporates hip circumference as well. This reflects differences in typical fat distribution patterns between biological males and females.
Generally no. The tape test under AR 600-9 is triggered only when a soldier exceeds the screening weight for their height. Soldiers within the weight standard proceed without a tape test.
The Hodgdon-Beckett equations used by the Army have a standard error of estimate of approximately 3–4% body fat. They tend to overestimate body fat in very lean individuals and underestimate it in some body types. For clinical precision, DEXA or underwater weighing is recommended.
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