What is Body Fat Percentage?
Body fat percentage is the proportion of your total body weight that comes from fat, as opposed to lean mass (muscle, bone, organs, water). Unlike BMI, which only considers height and weight, body fat percentage gives a clearer picture of body composition. This calculator uses the U.S. Navy method, which estimates body fat from measurements of your waist, neck, and (for women) hips. The formulas were developed at the Naval Health Research Center and are widely used because they require only a tape measure—no special equipment.
Body fat serves important functions: it stores energy, cushions organs, and helps regulate hormones. However, excess body fat—especially visceral fat around the abdomen—is linked to increased risk of heart disease, type 2 diabetes, and other conditions. Healthy ranges differ by gender: for men, fitness-level body fat is often around 14–17%, while for women it is typically 21–24%. Essential fat (the minimum needed for health) is about 2–5% for men and 10–13% for women.
The U.S. Navy method provides a reasonable estimate for most people, but it is not as precise as methods like DEXA scans or hydrostatic weighing. Accuracy depends on taking measurements correctly—waist at the navel, neck below the larynx, and hips at the widest point for women. Use this result as a general guideline and track changes over time rather than focusing on a single reading.