Body Fat Calculator

Body fat percentage represents the proportion of your total body mass that consists of adipose (fat) tissue. The U.S. Navy method estimates this using circumference measurements that correlate with subcutaneous and visceral fat deposits. The method was developed by Hodgdon and Beckett in 1984 at the Naval Health Research Center. It uses logarithmic regression equations derived from comparison with hydrostatic (underwater) weighing, which is considered a gold standard for body composition assessment. The equations take every measurement in inches, as DoD Instruction 1308.3 (2002, since replaced by DoD Instruction 1308.03) gives them, so this calculator divides the centimetres you enter by 2.54 before using them. For males, the equation uses the abdomen (measured at the navel) and neck circumferences along with height. The abdomen measurement captures abdominal fat, while the neck measurement serves as a proxy for lean mass. For females, the natural waist is measured at its narrowest point and hip circumference is added, because women tend to store more fat in the gluteal-femoral region. Body fat ranges are typically classified as: Essential fat (2-5% men, 10-13% women), Athletes (6-13% men, 14-20% women), Fitness (14-17% men, 21-24% women), Average (18-24% men, 25-31% women), Obese (25%+ men, 32%+ women). While the Navy method is convenient and reasonably accurate (a standard error of about 3–4 percentage points against hydrostatic weighing), it may overestimate body fat in muscular individuals. For clinical purposes, DEXA scans or hydrostatic weighing provide more precise measurements.