Sport & running
How do you calculate body fat with the Navy method?
Estimate body fat from neck, waist and hip measurements with the U.S. Navy formula.
Quick answer
The U.S. Navy body fat formula estimates adiposity from neck and waist circumferences (plus hips for women) — no calipers required, but technique matters more than the math. Example man **175 cm**, neck **38 cm**, waist **85 cm**: BF% ≈ **86.01 × log₁₀(85−38) − 70.04 × log₁₀(175/2.54) + 36.76** → roughly **18%**.
Estimated body fat
17 %
U.S. Navy method from circumference measurements. Not a medical diagnosis — ±3–4% vs DEXA is common. Measure in the morning, tape level and snug not tight.
How it works
It is a screening tool, not DEXA: ±3–4 percentage points is normal. Measure at the same time of day, exhale normally, tape parallel to the floor. For tracking trends, a skinfold caliper or smart scale adds convenience — the Navy numbers anchor the estimate without batteries.
Frequently asked questions
How accurate is the Navy method?+
Within a few percent of DEXA for many people if measurements are consistent. It fails on very lean lifters with thick necks or unusual fat distribution — use it for trends, not diagnosis.
Where exactly do I measure waist?+
At the navel level, at the end of a normal exhale — not sucked in, not bloated. For women the Navy formula also needs the widest hip circumference.
Navy vs smart scale body fat?+
Smart scales use bioimpedance — quick but hydration swings the reading ±2% day to day. Navy is free and repeatable if you measure the same way; many athletes use both and trust the trend.
What is a healthy body fat range?+
Rough guides: men athletes 6–13%, fit 14–17%, average 18–24%; women athletes 14–20%, fit 21–24%, average 25–31%. Age and sport matter — compare yourself to your past measurements, not Instagram.
As an Amazon Associate I earn from qualifying purchases — the price does not change for you.