How to measure
- Neck: just below the larynx (Adam's apple), with the tape sloping slightly down toward the front.
- Waist: men at the navel; women at the narrowest point of the waist. Relax and don't pull in your stomach.
- Hips (women): at the widest part of the buttocks.
Measure on bare skin, keep the tape snug but not tight, and take each measurement twice.
The formula
Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
All measurements are in inches. Metric inputs are converted first.
Body fat categories
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Obese | 32% and above | 25% and above |
Ranges from the American Council on Exercise.
Frequently asked questions
How accurate is the Navy method?
For most adults it lands within a few percentage points of methods like DEXA scans. It can be less accurate for very muscular or very lean people.
Is body fat better than BMI?
Body fat percentage separates fat from muscle, which BMI doesn't. Both are screening tools, not diagnoses.