Body Fat Calculator
US Navy method (waist + neck + hip) and BMI method side-by-side.
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Result
Body fat (Navy method)
17.0%
HealthyFitness
- CategoryFitnessHealthy
- BMI method (Deurenberg)rougher; uses BMI + age + sex20.1%
- Fat mass12.8 kg
- Lean mass62.2 kg
- BMI24.5
How to use this calculator
- Pick units and your sex.
- Measure your neck just below the larynx, parallel to the floor.
- Measure your waist at the navel, relaxed (not sucked in).
- For women: also measure the widest part of your hips.
- Take measurements in the morning, before eating.
About this tool
The US Navy body-fat formula is one of the most accessible methods that doesn't require special equipment — just a tape measure. It uses the difference between waist and neck (men) or waist+hip vs neck (women) along with height to estimate body fat percentage. Accuracy is within ±3% of DEXA scans for most people, but worse for very lean or very heavy individuals. The Deurenberg BMI method is even rougher (just BMI + age + sex) — included for comparison. For serious training or medical decisions, get a DEXA scan or hydrostatic weighing.
Frequently asked
±3% accuracy compared to DEXA scans for typical body compositions. Tends to under-estimate fat in very lean individuals and over-estimate in very obese ones.
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