About the Body Fat Calculator
Body fat percentage tells you what portion of your body weight is fat versus everything else — muscle, bone, water, and organs. Unlike BMI, which only looks at weight relative to height, this measure directly reflects body composition, so two people with the same BMI can have very different body fat percentages depending on how much muscle they carry.
This calculator uses the US Navy circumference method: a formula built from your height plus a few tape-measure readings (neck and waist for men; neck, waist, and hip for women). It was developed for the US Navy's own body composition standards specifically because it's accurate enough for practical use without calipers or a DEXA scan — just a flexible tape measure and a few centimeters of precision.
Your result includes a category — Essential Fat, Athletic, Fitness, Average, or Obese — based on the American Council on Exercise's sex-specific classification bands. These are descriptive ranges, not a diagnosis: body fat naturally varies with age, training history, and genetics. For the most reliable trend over time, measure at the same time of day, in the same conditions, and track changes over weeks rather than reacting to any single reading.
US Navy circumference method (Hodgdon & Beckett, 1984, Naval Health Research Center); body fat categories per the American Council on Exercise (ACE).