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Body Fat % Calculator for Athletes

Estimate your body fat percentage using the US Navy Method — just a tape measure needed. Athlete-specific category context so you know what your number actually means.

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Measure just below the larynx (Adam's apple), relaxed.
At navel for men. At narrowest point for women.
📐

Enter your measurements to estimate body fat % using the Navy Method.

Measure accurately. A flexible body tape measure is all you need to track your body fat % at home with the Navy Method.

View Measuring Tapes on Amazon →
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How the Navy Method Works

Male: BF% = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Female: BF% = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. All measurements in cm.

The Navy Method has approximately ±3–4% accuracy compared to DEXA scan. It's significantly more accurate than BMI for athletes and requires only a tape measure. Consistent measurement technique is essential — measure 3 times and average.

FAQs
It depends on the sport. Endurance athletes (marathon, triathlon): men 6–13%, women 14–20%. Strength athletes (powerlifting): men 8–18%, women 16–25%. Essential fat (minimum survivable): men ~3%, women ~12%. Below essential fat levels, performance and health deteriorate rapidly. Aesthetic goals should never override performance and health.
Accuracy is approximately ±3–4% compared to DEXA scan (gold standard). It's more accurate than BMI, skin callipers (if done incorrectly) and bioelectrical impedance (varies with hydration). For tracking changes over time — rather than absolute values — the Navy Method is excellent. Measure at the same time of day with consistent technique for best results.
The key triangle: moderate calorie deficit (300–500 kcal/day), high protein (2.0–2.4 g/kg), and maintained resistance training. Losing more than 0.5–1% of body weight per week significantly increases muscle loss risk. Prioritise sleep (7–9 hours) as growth hormone release during sleep supports lean mass preservation during a cut.
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