Body fat percentage calculator (US Navy)
Estimate your body fat percentage with the US Navy method using tape measurements.
US Navy method (circumference estimate). Measure relaxed, without tightening the tape. Not a substitute for professional assessment.
How the calculation works
This method, developed by the US Navy, estimates body fat from tape measurements — no bioimpedance scale or caliper needed. The idea: fat accumulates predictably at the waist (and, for women, the hips), while the neck reflects lean structure.
The formula is logarithmic and differs by sex:
- Men: use height, neck and waist →
waist − neck - Women: use height, neck, waist and hip →
waist + hip − neck
How to measure correctly
- Neck: just below the larynx, tape slightly sloping forward.
- Waist: at the navel (men) or narrowest part (women), relaxed, without holding your breath.
- Hip (women): at the widest part.
Always measure relaxed and without tightening the tape — 1 cm more at the waist changes the result noticeably.
Reference ranges
| Category | Men | Women |
|---|---|---|
| Essential | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fitness / healthy | 14–17% | 21–24% |
| Acceptable | 18–24% | 25–31% |
| Above | 25%+ | 32%+ |
It is an estimate. It works well for tracking trends over months, but does not replace methods like DEXA for an exact figure.
Examples
- Man, 175 cm, neck 38, waist 85: body fat ≈ 18% (acceptable range).
- Cutting 4 cm off the waist, all else equal, drops the result by several percentage points.
Frequently asked questions
Do I need the hip measurement?
Only for women. For men, the hip is not used.
Is it more reliable than a bioimpedance scale?
They are different methods with similar error. Bioimpedance varies with hydration and time of day; the tape method depends on measuring consistently. To track a trend, stick to one method.
Why does my body fat differ from BMI?
Because they measure different things: BMI only relates weight and height, without separating muscle from fat. Two people with the same BMI can have very different body-fat levels.
What percentage is healthy?
Generally ~14–24% for men and ~21–31% for women are healthy ranges. Very low values carry risks too — essential fat is necessary.
Sources and references
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Updated on June 17, 2026 · by Rafael Rossi · Methodology & sources