The US Navy tape method
Developed for military body composition screening, this method estimates body fat from circumference measurements and height using a logarithmic regression. For men it uses waist and neck; for women it adds the hip measurement, because fat distribution differs. It needs nothing but a tape measure and takes a minute.
Measuring properly
- Neck: just below the larynx, tape sloping slightly down at the front.
- Waist: men measure at the navel; women at the narrowest point of the torso.
- Hip: the widest point around the buttocks.
Measure first thing in the morning, before eating, standing relaxed and breathing out normally. Do not pull the tape tight enough to compress the skin. Repeat each measurement three times and use the middle value — inconsistent technique causes more error than the formula does.
Typical ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
Accuracy and its limits
Against DEXA scanning, the Navy method typically lands within about three to four percentage points, and it is least reliable at the extremes — very lean and very heavy people both tend to be mis-estimated. Its real strength is consistency: measured the same way each month, the direction of change is meaningful even if the absolute number is approximate. Read it alongside your BMI, and see why body composition matters more than weight alone.