Loona Calculators
All you need is a tape measure. The US Navy circumference method estimates body fat from your height, neck and waist (plus hips for women) — no scales, scans or clinic visit required for a solid estimate.
Against clinical methods it is usually within a few percent when measurements are taken carefully. Tape tension and posture matter — measure at the same time of day for comparable results.
They follow the American Council on Exercise ranges — for men: Essential up to 5%, Athletes 6-13%, Fitness 14-17%, Average 18-24%, Obese 25% and above; women's ranges run higher, as healthy female body fat is naturally higher.
The Navy equations were fitted to thousands of measured sailors; the waist-minus-neck difference tracks abdominal fat while cancelling out general frame size.