How it works
The U.S. Army screens every Soldier against weight-for-height tables under the Army Body Composition Program (AR 600-9). When a Soldier exceeds the screening weight for their height and sex, the unit measures circumference at designated anatomical landmarks — the tape test — and plugs those readings into a logarithmic equation to derive a body-fat percentage. That percentage is then compared against age-bracketed maximums to determine compliance with retention standards.
This is a regulatory gate, not a fitness evaluation. A Soldier who exceeds their allowable maximum can be flagged, entered into a weight-control program, and made ineligible for promotion, professional military education, or reenlistment until they return to standard. Army Directive 2023-11 revised the thresholds, so this tool checks against the current allowable limits — not the older appendix tables from the original regulation.
Three measurements drive the calculation for male Soldiers: neck circumference (narrowest point below the larynx), abdominal circumference (level with the umbilicus), and height. Female Soldiers add a hip measurement (widest point of the buttocks) and use the natural waistline — the narrowest part of the torso between the lower rib and the iliac crest — rather than the navel. All measurements round to the nearest half-inch before entering the equation.
The formula
Male %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Female %BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
All measurements in inches. The logarithm is base-10.
Worked example
Consider a 29-year-old male Soldier, 70 in tall, with a neck of 15.5 in and an abdominal circumference of 34 in.
Waist − neck: 34 − 15.5 = 18.5
log10(18.5) = 1.2672
log10(70) = 1.8451
86.010 × 1.2672 = 108.99
70.041 × 1.8451 = 129.23
%BF = 108.99 − 129.23 + 36.76 = 16.5%
For a 29-year-old male, the Army maximum is 24% (age 28–39 bracket). This Soldier passes with margin.
Now a 24-year-old female Soldier, 65 in tall, neck 13.5 in, natural waist 29 in, hip 38 in.
Waist + hip − neck: 29 + 38 − 13.5 = 53.5
log10(53.5) = 1.7284
log10(65) = 1.8129
163.205 × 1.7284 = 282.03
97.684 × 1.8129 = 177.03
%BF = 282.03 − 177.03 − 78.387 = 26.6%
For a 24-year-old female, the Army maximum is 32% (age 21–27 bracket). This Soldier also passes.
The full compliance table:
| Age bracket | Male maximum | Female maximum |
|---|---|---|
| 17–20 | 20% | 30% |
| 21–27 | 22% | 32% |
| 28–39 | 24% | 34% |
| 40+ | 26% | 36% |
A Soldier at or below their bracket threshold is compliant. Anything above triggers ABCP action.
Things to watch
Measurement technique drives the result more than any other variable. The Army requires the same person to take all readings, the tape must sit horizontal and snug without compressing skin, and each site is measured twice — three times if the first two differ by more than one inch, then averaged. A tape pulled too tight at the neck or too loose at the abdomen can shift the estimate by two or three percentage points, enough to flip a pass to a fail.
Height also carries disproportionate weight because it sits inside the logarithm. A Soldier measured half an inch shorter than actual will see a slightly higher estimated body fat. Ensure height is current, particularly for older Soldiers who may have lost stature.
This calculator produces an estimate, not professional advice. The Army uses the same equation, but unit-level tape tests follow specific procedural rules — who measures, how many repetitions, where exactly the tape sits — that a self-measurement cannot fully replicate. If you are preparing for an official screening, have a trained measurer take the readings.