How to measure
- Neck: just below the larynx, tape sloping slightly downward at the front. Do not flare the tape over the trapezius.
- Waist: for men, level with the navel; for women, at the narrowest point. Relaxed, at the end of a normal exhale.
- Hips (women): at the widest point, feet together.
Keep the tape snug but not compressing the skin, measure twice, and always at the same time of day — morning before food is the most repeatable.
Methodology
The formulas come from the US Naval Health Research Center. For men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450, in centimeters. Women use waist + hips − neck with separate coefficients. Circumference methods estimate fat distribution from where you store it, which is why they track trends well even if any single reading is a few points off.
Reference ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fit | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
Know your body fat? Feed it into the FFMI calculator to see how much muscle you carry for your height, or the TDEE calculator to plan your nutrition.