Lean Body Mass Calculator
Lean body mass (LBM) is the weight of everything in your body except fat. Knowing your LBM helps you set more accurate nutrition targets and understand your body composition beyond just total body weight.
Formulas
Boer (1984) — Recommended
Men: LBM = 0.407 × weight (kg) + 0.267 × height (cm) − 19.2
Women: LBM = 0.252 × weight (kg) + 0.473 × height (cm) − 48.3
James (1976)
Men: LBM = 1.1 × weight (kg) − 128 × (weight / height)²
Women: LBM = 1.07 × weight (kg) − 148 × (weight / height)²
Hume (1966)
Men: LBM = 0.3281 × weight (kg) + 0.3393 × height (cm) − 29.5336
Women: LBM = 0.2994 × weight (kg) + 0.7861 × height (cm) − 59.3724
Why LBM Matters
- Protein targets: Most recommendations are set per kg of LBM (or body weight), with higher demands for athletes.
- Drug dosing: Many medications are dosed based on LBM, not total body weight.
- Progress tracking: LBM can increase while total weight stays the same — a sign of muscle gain and fat loss.