Body Fat % (US Navy)
Measure waist and neck (and hip for women). Choose Metric or Imperial; metric is converted to inches for the Navy formulas.
cm
cm
cm
Body Fat %:
—
Enter measurements.
Guide
Men: Essential 2–5, Athletes 6–13, Fitness 14–17, Average 18–24, Obese 25+
Women: Essential 10–13, Athletes 14–20, Fitness 21–24, Average 25–31, Obese 32+
FAQ
What formula is used?
The official US Navy method: for men,
86.010·log10(waist − neck) − 70.041·log10(height) + 36.76; for women,
163.205·log10(waist + hip − neck) − 97.684·log10(height) − 78.387.
All measurements calculated in inches.
How should I measure?
Measure neck at the narrowest, waist at the navel (relaxed), and hip at the widest (women). Stand upright, exhale normally, keep the tape level and snug—not tight.
Can I enter centimeters?
Yes. We accept cm and convert to inches internally before applying the US Navy equations.
How accurate is this?
It’s an estimate. More precise methods (DEXA, hydrostatic) exist, but they’re less accessible.