Body fat calculator (US Navy method)
Hips are measured for women only.
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This calculator gives an estimate for healthy adults. It is not medical advice.
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The US Navy method estimates body fat from circumference measurements. Fat tends to collect around the waist, while the neck reflects your frame, so the gap between the two — together with your height — predicts body fat surprisingly well. For women the hips are added, because women store more fat there.
In studies, the method usually lands within about 3–4 percentage points of lab methods such as DEXA. That is similar to bioimpedance scales and much better than BMI for people with a lot of muscle. Its biggest strength is consistency: measured the same way every time, it shows reliably whether your body fat is going up or down.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Measure in the morning, before eating, with a soft tape snug against the skin but not compressing it. Waist: men at the navel, women at the narrowest point. Neck: just below the larynx, with the tape sloping slightly down to the front. Hips (women): at the widest point of the buttocks.
Take each measurement two or three times and use the average. Re-measure every two to four weeks under the same conditions — the trend over time matters more than any single number.
How accurate is the US Navy body fat method?
For most people it is within about 3–4 percentage points of a DEXA scan. It is less accurate for very lean or very obese people and for people whose fat is distributed unusually, but it tracks changes well.
What is a healthy body fat percentage?
For general health, roughly 10–20% for men and 18–28% for women. Athletes are often lower. Going below essential fat (about 2–5% for men, 10–13% for women) is unhealthy.
Why is body fat a better measure than BMI?
BMI only uses height and weight, so it can't tell muscle from fat. Body fat percentage shows what your weight is made of — useful when you are building muscle and losing fat at the same time.
