How the AR 600-9 tape equations work
Army Regulation 600-9, The Army Body Composition Program (16 July 2019, with an administrative revision dated 27 February 2025), publishes circumference equations in Table B-5. For men: % body fat = 86.010 × log10(abdomen − neck) − 70.041 × log10(height) + 36.76. For women: % body fat = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. All measurements go into the formula in inches. Those are the same Hodgdon-style logarithms used in the Navy body fat calculator, but the Army page adds the regulation’s measurement notes, official sample checks, and Table B-2 limits.
Measurement details matter. The neck is taken just below the larynx. For males, abdomen is measured at the navel, level, at the end of a normal relaxed exhale — not after sucking in. For females, waist is the narrowest point, usually about halfway between the navel and the lower sternum, and hip is at the greatest protrusion of the buttocks with the tape level. The regulation tells units to take sequential sets of measurements and, in the official samples, to report body fat as a whole percent. This page shows the raw estimate to one decimal and a whole-number value for the Table B-2 comparison.
Table B-2 maximums in the same regulation are 20% (male) / 30% (female) at ages 17–20; 22% / 32% at 21–27; 24% / 34% at 28–39; and 26% / 36% at 40 and older. A “pass” or “above the limit” label here only compares your tape estimate with that table. It is not a command decision, a medical finding, or a substitute for a unit weigh-in. AR 600-9 also uses a height-and-weight screening table (Table B-1) before a tape is required; that screening table is not reproduced here. Read the current official publication when something official is at stake: AR 600-9 on armypubs.army.mil.
Later official messages have discussed other assessment options. This calculator implements the equations we could verify in the AR 600-9 PDF cited above. If your unit is using a different current method, follow that official instruction instead of a webpage.
A tape estimate can miss by several points compared with a clinical method. Use consistent timing and landmarks if you track yourself. This is not medical advice, and it is not authorization to change a diet or training plan in an extreme way to chase a number.
Frequently asked questions
Is this the official Army calculator?
No. Official assessments follow current Army publications, trained tape teams, and unit procedures. This page applies the Table B-5 equations from AR 600-9 so you can understand the math. Commanders, not websites, own official results.
How is this different from the Navy tape calculator?
The logarithms are the same family of equations. The Army page adds Table B-2 age limits, official rounding for the comparison, and Army-specific landmark notes (including male abdomen at the navel). Use the Navy page if you are following a Navy standard, and this page if you are studying the Army regulation.
Do I have to tape if I already meet height and weight?
AR 600-9 says that if a Soldier is within the Table B-1 weight-for-height screen, a body-fat assessment is not required in the ordinary case, though a commander can still direct one. This site does not implement Table B-1. Check the regulation.
Why should I round to a whole percent?
The sample calculations in Table B-5 round the solved equation to the nearest whole percent. This page shows a tenth of a percent so you can see the raw math, and a whole number for the table comparison. Official worksheets may also use specific rounding on each tape reading (for example, neck up, abdomen down, to the half inch).
Can I use this while pregnant or after giving birth?
No. The regulation treats pregnancy and postpartum periods as special cases, and circumference math is not a suitable self-test in those situations. Follow medical and official guidance instead.