Estimate body fat using the legacy multi-site circumference formula and compare it with historical age/sex limits. This tool does not determine compliance with current Army policy.
Historical method: current Army screening has changed. The outputs below are legacy estimates only; see the current-policy note in Methodology.
Advanced options
How to use our Army Body Fat Calculator
- Choose Sex and enter Age in whole years.
- Enter height as whole feet plus the remaining inches. Enter neck and waist measurements in inches; female mode also requires hip circumference in inches.
- Choose nearest half-inch rounding or exact entered values, then click Calculate.
- Read the legacy estimate and historical limit comparison. Current Army screening uses a different policy; consult the policy note and official sources below.
Definitions
Body fat percentage: an estimate from body measurements, not a direct laboratory measurement.
Circumference: distance around the neck, waist or hips.
Historical limit: the age/sex percentage threshold retained for legacy comparison, not a current eligibility decision.
log10: the base-10 logarithm used in the legacy equations.
Common mistakes and quick fixes
Mixed units: this version accepts inches for circumferences and feet plus inches for height. Convert centimeters to inches by dividing by 2.54 before entering them.
Invalid measurements: male waist must exceed neck; female waist plus hip must exceed neck. Recheck measurement placement rather than changing numbers just to pass validation.
Missing hip measurement: enter it in female mode.
Age: enter whole years within the supported age range.
Wrong policy: the historical comparison is not a current Army pass/fail result. This version does not provide body-weight, fat-mass or lean-mass calculations.
Limitations & Key Assumptions / Boundary Conditions
This is a legacy circumference estimate. Measurement placement and rounding affect the result; it is not a direct body-composition measurement.
All circumferences are entered in inches. Height combines the feet and inches fields. Male mode ignores hip input.
The stored age/sex limits are for historical comparison only. Current screening, official measurement technique and administrative decisions require current Army guidance.
Methodology
Legacy equations
After validation and the selected rounding, height is converted from feet plus inches to total inches.
Male: body fat (%) = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76.
Female: body fat (%) = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387.
The estimate is compared with the stored historical age/sex limit. This preserves legacy comparisons and does not implement current Army screening.
Worked example
A male aged 25 with height 5 ft 10 in, neck 16 in and waist 34 in, using exact entered values, has an estimate of 15.4934763%, displayed as 15.5%. The stored historical limit for this age band is 22%. No fat-mass or lean-mass output is calculated.
Current policy note
Checked September 19, 2026: the U.S. Army Sustainment Command describes Army Directive 2026-13 as replacing the former tape test with waist-to-height screening. This legacy calculator does not perform that assessment. See the official source and follow current unit measurement instructions.
Sources
The linked current-policy source describes why the legacy calculation above must not be used as a current compliance decision.