Estimates body fat percentage from circumference measurements using the U.S. Navy tape method (log formula). Men need neck and waist (waist measured at the navel); women need neck, waist at the narrowest point, and hips at the widest. Results are service-screening style estimates, not hydrostatic weighing or DEXA—tension on the tape and measurement sites dominate error.
U.S. Navy circumference method (measurements in inches):
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
Requires male waist > neck and female waist + hip > neck. Official readiness tables may differ; this is the published log equation only.
This Navy tape body fat estimator applies the formulas described on this page to the values you enter. Outputs are not financial, tax, legal, or medical advice.
Last reviewed: 2026-04-17
This page applies the published Navy circumference log equation to your measurements. Official screening also depends on measurement protocol, rounding, and applicable tables—your result here is an estimate only.
The male Navy formula uses log(waist − neck); that difference must be positive. Recheck tape placement (male waist at the navel per Navy guidance).
No. Tape estimates can be useful for tracking trends but differ from lab methods—hydration and measurement tension alone shift outcomes.