Body Fat Percentage Calculator: US Navy Method
The US Navy body fat calculation is the most widely used tape-measure-based method for estimating body fat percentage without expensive equipment. It was developed for military fitness standards and has been validated against hydrostatic weighing and DEXA scan results for general accuracy. The method uses height, neck circumference, and waist circumference (plus hip circumference for women) to estimate body fat percentage.
US Navy Body Fat Formula
For Men:
Body Fat % = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76
For Women:
Body Fat % = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387
All measurements in inches. The calculator converts automatically from centimeters if you select that unit.
Body Fat Category Reference
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5% | 10–13% |
| Athlete | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average / Acceptable | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
How to Reduce Body Fat
Body fat reduction requires a sustained caloric deficit (consuming fewer calories than you expend). The most effective approach combines:
- Caloric deficit: 300–500 calories below maintenance for steady loss (~0.5–1 kg/week).
- Resistance training: Preserves muscle mass during a deficit so weight lost is primarily fat.
- High protein intake: 1.6–2.2g protein per kg bodyweight supports muscle retention.
- Sleep and recovery: Poor sleep increases cortisol and hunger hormones, making fat loss significantly harder.