This tool is for general informational and fitness purposes only and is not medical advice. The US Navy method is an estimate and can differ from a clinical body-composition test. Talk to a doctor or qualified professional before making health, diet, or training decisions.
Enter your measurements
Use inches. Measure with a flexible tape, snug but not tight.
How the US Navy body fat method works
The US Navy circumference method estimates body fat from a few tape measurements and your height, using formulas the Navy validated against more precise tests. For men it uses the waist minus the neck; for women it adds the hip measurement. The formula in imperial units is, for men, 86.010 times the base-10 logarithm of (waist minus neck) minus 70.041 times the log of height plus 36.76. For women it is 163.205 times the log of (waist plus hip minus neck) minus 97.684 times the log of height minus 78.387. Fat mass is then your body fat percentage times your weight, and lean mass is whatever is left.
Frequently asked questions
How does the US Navy body fat method work?
It estimates body fat from a few tape-measure circumferences and your height. For men it uses neck and waist; for women it adds the hip. These go into a logarithm-based formula the Navy developed by comparing tape measurements to more precise body-fat tests.
Where should I measure my neck, waist, and hips?
Measure the neck just below the larynx with the tape sloping slightly down at the front. For men, measure the waist horizontally at the navel; for women, at the narrowest point. Hips are measured at the widest part of the buttocks. Keep the tape snug but not compressing the skin, and do not suck in.
How accurate is this calculator?
For most people in the 15 to 30 percent body-fat range it is usually within about three to four percent of a DEXA scan. It is less precise than DEXA or hydrostatic weighing, but it is free and only needs a tape measure. Treat it as an estimate.
What is a healthy body fat percentage?
Often-cited general ranges are roughly 10 to 20 percent for men and 18 to 28 percent for women, with athletes lower. Healthy ranges vary with age, sex, and goals, so use these only as a rough guide and ask a doctor for personalized advice.
Is my data saved anywhere?
No. All calculations run entirely in your browser. Nothing you enter is uploaded or saved on a server.
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Disclaimer: Results are estimates for general informational purposes only and are not medical advice. Always double-check important figures and consult a qualified professional.