Lean Body Mass Calculator
Calculate your lean body mass (LBM) — everything in your body that isn't fat. Essential for accurate BMR and macro calculations.
What Is Lean Body Mass (LBM)?
Lean body mass is your total body weight minus fat. It includes muscle, bones, organs, water, and everything else. LBM is metabolically active tissue — it burns calories. Knowing your LBM helps you calculate BMR more accurately using the Katch-McArdle formula.
LBM Estimation Formulas
When you don't know your body fat percentage, the Boer, James, and Hume formulas estimate LBM from height and weight. The direct method (using body fat %) is most accurate.