Body fat percentage tells you what BMI cannot: how much of your weight is fat versus everything else. Two people can share the same BMI while one is lean and athletic and the other carries excess fat — the tape-measure method separates those cases without any special equipment.
The US Navy method was developed to assess service members quickly and correlates well with lab measurements for most people. Men enter height, neck and waist; women add hips. Measure in the morning, relaxed, with the tape snug but not compressing the skin.
Part of the Health Calculators collection on CountCrunch.
How to take the measurements
- Neck: just below the Adam's apple, tape perpendicular to the neck, looking straight ahead.
- Waist: at the navel for men; at the narrowest point for women. Relax and breathe out normally — do not suck in.
- Hips (women): around the fullest part of the buttocks, feet together.
- Height: standing straight, without shoes.
The Navy formula
All measurements in the same units. The result is body fat as a percentage of total weight; the calculator also shows fat mass and lean mass in kg or lb.
Healthy body fat ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fit | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Ranges come from the American Council on Exercise. Women carry more essential fat for hormonal and reproductive health, which is why healthy ranges differ by sex.
Frequently asked questions
How accurate is the US Navy body fat method?
Typically within 3–4 percentage points of lab methods like DEXA for average builds. It is less reliable for very muscular or very lean people, and consistency of measurement matters more than perfection — measure the same way each time to track trends.
Where exactly do I measure my waist?
Men: around the navel. Women: at the narrowest point of the torso, usually above the navel. Measure relaxed after a normal exhale, with the tape level and snug.
What is a healthy body fat percentage?
For men roughly 14–24% and for women 21–31% covers fit-to-average. Athletes run lower. Below essential-fat levels (about 5% men, 13% women) health risks rise.
Is body fat percentage better than BMI?
For individuals, usually yes — it distinguishes fat from muscle, which BMI cannot. They work best together: BMI as a quick screen, body fat for the detail.