Calculator · Performance Lab
Body Fat Calculator
Estimate your body-fat percentage with the U.S. Navy circumference method — fast, no device, with clear classification.
Ergebnis
- Body-fat percentage
- 15.3%
- Classification
- Fitness
U.S. Navy estimate — robust orientation without a device.
Sex-specific reference ranges.
The circumference method gives a very good estimate but is not DEXA. Expect ±3 % accuracy. What matters is the trend over time with consistent measurement technique.
Explained
What this calculator does for you
Body-fat percentage says far more about your composition than weight or BMI alone. It separates fat-free mass (muscle, bone, water) from fat tissue.
The U.S. Navy method uses body circumferences to estimate body fat. It has been established for decades, costs nothing and works at home with a tape measure.
Important: an estimate is an estimate. What matters is consistency — same time of day, same conditions, same technique.
Science
Scientific background
The method was developed in the 1980s by the Naval Health Research Center (Hodgdon & Beckett 1984). It correlates with hydrostatic weighing across many studies at r ≈ 0.90.
Men: 495 / (1.0324 − 0.19077 · log₁₀(waist − neck) + 0.15456 · log₁₀(height)) − 450.
Women: 495 / (1.29579 − 0.35004 · log₁₀(waist + hip − neck) + 0.221 · log₁₀(height)) − 450.
Accuracy: ±3 % vs. gold-standard methods like DEXA — very good for a tape measure.
Examples
Practical examples
Male, 180 cm / neck 38 / waist 84
≈ 13.8 % body fat → 'Athletic'. Solid fitness range.
Female, 168 cm / neck 32 / waist 70 / hip 95
≈ 22.4 % body fat → 'Fitness'. Healthy and performance-capable.
Avoid these
Common mistakes
- 01Pulling the tape too tight — systematically biases low.
- 02Comparing different times of day or different training/eating states.
- 03Over-interpreting single readings. Trends over 4–8 weeks matter, not a single day.
- 04Mixing readings with a bioimpedance scale — don't mix methods.
Recommendations
Further recommendations
- 01Measure every 2–4 weeks under identical conditions — morning, fasted, pre-training.
- 02Log the values. Change matters more than absolute number.
- 03Combine with photos in the same pose and lighting. Image + number = honest read.
FAQ
Frequently asked questions
- How do I measure properly?
- Morning, fasted, relaxed. Tape snug, not pressing in. Measure several times and average.
- Why do women need hip circumference?
- Women store fat differently. Hip measurement significantly improves the estimate.
- How accurate is it?
- About ±3 % vs. DEXA. Very useful for tracking trends — not absolute truth.
- What is a 'healthy' value?
- Men: 10–18 % is fit, 14–17 % is aesthetic. Women: 18–25 % is fit, 21–24 % is aesthetic. Below the essential range it becomes unhealthy.
- Caliper, scale or tape?
- Bioimpedance scales fluctuate strongly with hydration. Calipers are more accurate but need practice. The circumference method is the best trade-off of effort and signal.
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Knowledge Hub
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