Body Fat Calculator
Estimate body-fat percentage with a tape measure — the U.S. Navy method.
Body fat
16.1%
FitnessThe U.S. Navy method estimates body-fat percentage from circumference measurements. It needs only a tape measure and gives a repeatable number that's great for tracking change over time.
How it's calculated
Measure your neck, waist (and hips for women) in centimetres, relaxed, without compressing the skin. Enter them with your height and sex. Consistency matters more than perfection — measure the same way each time.
Men: 495 / (1.0324 − 0.19077·log10(waist−neck) + 0.15456·log10(height)) − 450
How to read your result
Treat the result as an estimate (±3–4%). What matters is the trend: a falling number on consistent measurements means you're losing fat. Categories range from essential fat through athletic, fitness, average and high.
Frequently asked questions
- How accurate is the Navy method?
- It's typically within 3–4% of more advanced methods like DEXA, and far more accurate for tracking change than a single body-fat scale reading.
- Where exactly do I measure?
- Neck just below the larynx; waist at the navel for men; waist at the narrowest point and hips at the widest for women. Keep the tape level and snug, not tight.
- Why does it ask for hips for women only?
- The female formula includes hip circumference to better account for fat distribution; the male formula does not need it.