Estimate your body fat percentage using the US Navy method — no equipment needed beyond a tape measure.
Hips measured for women at the widest point. Waist at narrowest (1 inch above belly button). Neck just below larynx.
The US Navy method estimates body fat from circumference measurements. For men: enter neck, waist, and height. For women: enter neck, waist, hips, and height. The formula uses logarithms to estimate fat percentage without calipers or lab equipment.
The US Navy circumference method estimates body fat percentage using measurements of your height, neck, and waist (for men), with hips added for women. It was developed by the US Navy to assess fitness without requiring expensive equipment. It uses a logarithmic formula that correlates these measurements with body density and fat percentage.
BMI only uses height and weight. It can't tell the difference between muscle and fat. A muscular athlete and an overweight sedentary person can have identical BMIs. Body fat percentage directly measures what proportion of your body is fat, making it a better indicator of health risk and physical composition than BMI.
The Navy method has a margin of error of about 3-4% compared to DEXA scans (the gold standard). It's less accurate than underwater weighing or DEXA, but it's free, fast, and reliable enough for tracking changes over time. Measure consistently — same time of day, same technique — to get meaningful comparisons.
For men, 6-17% is athletic/fit, 18-24% is acceptable, and 25%+ is obese. For women, 14-24% is athletic/fit, 25-31% is acceptable, and 32%+ is obese. These are general guidelines — healthy ranges shift with age, and athletes may carry more muscle mass that affects these readings.