Body Fat Calculator
A tape measure and three numbers: get your body fat percentage, fat mass and lean mass with the US Navy method.
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Example
A man 5 ft 10 in, waist 34 in, neck 15 in reads about 18 % body fat. At 180 lb that is 32 lb of fat and 148 lb of lean mass.
Method and formula
US Navy equations (Hodgdon and Beckett, 1984). Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387, all in centimetres.
Categories follow the American Council on Exercise ranges.
Limits
- Typical error is 3 to 4 points versus DEXA; consistency of measurement matters more than the absolute value.
- Measure at the navel for the waist, below the larynx for the neck, at the widest point for hips, tape snug and horizontal.
FAQ
How accurate is the Navy method?
Within about 3 to 4 points of a DEXA scan for most people. Use the same conditions each time and track the trend.
What is a healthy body fat percentage?
Roughly 10 to 20 % for men and 18 to 28 % for women is considered fit to average. Athletes sit lower, but essential fat must be preserved.
Free educational tool. Body composition, calorie and heart rate values are estimates from published formulas, not medical measurements. They do not replace a professional assessment. No weight-loss recommendation is intended for people under 18.