The US Navy method estimates body fat percentage from a few tape-measure readings — no calipers or scans needed.
86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. ACE-style bands then label the percentage. A circumference estimate, not DEXA or a clinical reading.
This circumference-based method can be off by several percentage points compared to DEXA or hydrostatic weighing — treat it as a ballpark estimate, and best used to track your own trend over time with consistent measuring technique.
Formula: US Navy circumference method (Hodgdon & Beckett, Naval Health Research Center, 1984), inches-based regression. Categories: American Council on Exercise (ACE) body-fat classification.
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Acceptable | 25–31% | 18–24% |
| Obese range | 32%+ | 25%+ |
This uses the US Navy tape-measure method, a circumference-based estimate that only needs a few measurements rather than specialized equipment. For men, the formula is 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76; for women, it's 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387, both using measurements in inches.
The resulting percentage is then classified using ACE-style bands (essential fat, athletic, fitness, average, and obese), giving context for what your number means relative to commonly used fitness categories rather than just a raw percentage.
This is a circumference-based estimate, not a DEXA scan, hydrostatic weighing, or other clinical body composition measurement — those methods directly measure body composition and are considerably more accurate. The Navy method is popular because it only needs a tape measure, but treat the result as a reasonable estimate for tracking trends over time, not a precise clinical reading.
It's a reasonable field estimate, but less precise than clinical methods like DEXA scans or hydrostatic weighing, which directly measure body composition. Its advantage is that it only needs a tape measure and a few circumference readings, making it practical for regular self-tracking.
Waist, neck, and height for men; waist, hip, neck, and height for women — all measured in inches for the formula used here, though the page may convert other units for you.
They classify your estimated body fat percentage into commonly used categories (like essential fat, athletic, fitness, average, and obese), giving context for where your number sits relative to typical population ranges.
Because typical body fat distribution differs by sex, so the Navy method uses a formula calibrated separately for each, incorporating the measurements found to correlate best with body fat percentage for men versus women.