Army Body Fat Calculator

The US Army body fat percentage method uses circumference measurements, neck and waist plus hips for women, instead of underwater weighing or a DEXA scan. It was designed for field use: fast, repeatable, and needing nothing but a flexible tape measure and a formula.

Formulas:

For Men: Body Fat % = 86.010 × log₁₀(Waist − 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 in inches.

How to measure correctly:

• Neck: Measure just below the larynx (Adam’s apple), perpendicular to the long axis. Round UP to nearest 0.5 inch.
• Waist (men): At the navel, against the skin. Round DOWN to nearest 0.5 inch.
• Waist (women): At the narrowest point. Round DOWN to nearest 0.5 inch.
• Hip (women): At the widest point, parallel to the floor. Round DOWN to nearest 0.5 inch.
• Height: Measure without shoes, feet together. Round DOWN to nearest 0.5 inch.

US Army body fat standards (maximum allowed):

Worked example (Male): Height: 70 inches | Waist: 34 inches | Neck: 15.5 inches

Body Fat = 86.010 × log₁₀(34 − 15.5) − 70.041 × log₁₀(70) + 36.76 = 86.010 × log₁₀(18.5) − 70.041 × log₁₀(70) + 36.76 = 86.010 × 1.26717 − 70.041 × 1.84510 + 36.76 = 108.99 − 129.23 + 36.76 = 16.5%

At age 28, this male passes the standard shown above (maximum 24%).

The circumference difference is what drives the answer

Notice that only one number in the male formula does any real work: waist minus neck. Height enters as a correction, and everything else is a constant. Add an inch to the waist and the result moves about 2 percentage points at typical dimensions. Add an inch to the neck and it moves the other way by roughly the same amount.

That is also the method’s weakness. It cannot tell a thick neck built by training from a thick neck built any other way, so it flatters people with heavy necks and penalises long-waisted ones. Measure carefully, and measure the same way each time if you are tracking a trend, because a half-inch of tape error swings the result by a full point.

Which standard is this?

The formulas here are the long-standing Department of Defense circumference method, the one everyone calls the tape test, and the age-banded limits are the Army table that went with it. Two things to know before you rely on the number:

• The Army revised its own programme in 2023, moving to a single abdominal circumference measurement rather than the neck-and-waist calculation, and restructuring the limits. If you are being taped for record, use the current regulation and the version your unit is actually running.
• Every service sets its own maximums, and they differ. The Navy, Marine Corps and Air Force each have separate instructions, and the Air Force stopped using a body fat percentage entirely. Do not read an Army pass as a pass anywhere else.

Accuracy note: this method sits roughly 3 to 4 percentage points away from a DEXA scan, in either direction. It tends to overestimate body fat in muscular people, which is the complaint you hear most often about it, and to underestimate it in people who are lightly built but carry fat centrally.