Units, Sex, Weight, Height, Extra inches (US only)
Body Fat Calculator (US Navy Method)
Estimate body fat percentage from a few tape measurements.
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How this calculator works
The US Navy method predicts body fat from circumferences instead of skinfolds or scans. Men need neck and waist; women also need hips. It is usually within a few percentage points of lab methods, and the same tape and technique each time matter more than the exact number.
Formula
- Men: 495 / (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
- Women: 495 / (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
- All measurements in centimeters. Fat mass = weight × body fat %; lean mass = weight − fat mass.
Worked example
Man, 80 kg, 178 cm, neck 38 cm, waist 88 cm
- Units
- Metric (kg, cm)
- Sex
- Male
- Weight
- 80
- Height
- 178
- Neck
- 38
- Waist
- 88
Result18.7% body fat
Average range for men (ACE categories).
Body fat categories (American Council on Exercise)
| 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 |
Things to keep in mind
- Measure the waist at the navel for men and at the narrowest point for women, the neck just below the larynx, and hips at the widest point.
- For general information only. It is not medical advice; talk to a health professional about your own situation.
Frequently asked questions
How accurate is the Navy body fat method?
For most people it lands within about 3 to 4 percentage points of DEXA or hydrostatic weighing. It is less reliable for very lean or very muscular people.
Where exactly do I measure my waist?
Men measure horizontally at the level of the navel. Women measure at the narrowest part of the waist. Keep the tape snug but not compressing the skin, and measure after a normal exhale.
Do I need my hip measurement?
Only women do. The women's equation uses waist plus hip minus neck; the men's equation ignores hips.
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Results are estimates based on the values you enter and the published method shown above. They do not replace professional medical, financial or legal advice. Method reviewed October 7, 2026. About this site