Lean Body Mass Calculator

Lean body mass (LBM) is your weight minus your body fat: muscle, bone, organs and water. The calculator uses three common formulas with height (H, cm) and weight (W, kg); US units are converted first: • Boer — men: 0.407W + 0.267H − 19.2; women: 0.252W + 0.473H − 48.3 • James — men: 1.1W − 128 (W/H)²; women: 1.07W − 148 (W/H)² • Hume — men: 0.32810W + 0.33929H − 29.5336; women: 0.29569W + 0.41813H − 43.2933 Example: a man who is 175 cm (5 ft 9 in) and 70 kg (154 lb) gets 0.407 × 70 + 0.267 × 175 − 19.2 = 56.0 kg (123.5 lb) with the Boer formula. His fat mass is 70 − 56.0 = 14.0 kg, about 20% body fat. The formulas are built on average body types, so they are less accurate for very muscular or very heavy people. Bioimpedance, a DEXA scan or skinfold calipers give a more precise number.