Estimate your body fat percentage using the U.S. Navy circumference method. All you need is a tape measure.
Frequently Asked Questions
The U.S. Navy method has an accuracy of approximately plus or minus 3-4% when measurements are taken correctly. It correlates well with hydrostatic weighing and DEXA scans for most people. For very muscular or very lean individuals, it may be less accurate.
Healthy body fat ranges vary by sex. For men: essential fat is 2-5%, athletes 6-13%, fitness 14-17%, acceptable 18-24%, obese 25%+. For women: essential fat is 10-13%, athletes 14-20%, fitness 21-24%, acceptable 25-31%, obese 32%+.
Measure your waist at the navel (belly button) level. Stand relaxed and do not suck in your stomach. The tape should be snug but not compressing the skin. Take the measurement at the end of a normal exhale.
Measure your neck circumference just below the larynx (Adam's apple). Keep the tape level and perpendicular to the long axis of your neck. Look straight ahead and do not flex your neck muscles.
Neck circumference correlates with lean body mass and serves as a proxy for overall muscularity. A larger neck relative to waist size indicates more muscle mass and lower body fat percentage. The formula uses the ratio of waist-to-neck (and hip for women) to estimate fat.
Take measurements first thing in the morning before eating. Use a flexible tape measure. Measure each site twice and use the average. Stand naturally and do not flex.