A Lean Body Mass (LBM) calculator estimates the mass of everything in your body except fat, muscles, bones, organs, blood, skin, and water.
About this calculator
A Lean Body Mass (LBM) calculator estimates the mass of everything in your body except fat, muscles, bones, organs, blood, skin, and water. LBM is a more informative measure than total body weight for fitness and health because it separates functional tissue from fat storage.
LBM is used in medical dosing calculations, fitness programming, nutrition planning, and tracking body recomposition progress. An increase in LBM with stable or lower body weight indicates successful muscle building.
Common uses
- Track muscle gain progress during a resistance training program
- Calculate protein requirements based on lean body mass
- Monitor body recomposition (gaining muscle, losing fat)
- Use LBM for medication dosing calculations
Frequently asked questions
What is the formula for lean body mass?
The Boer formula: For males: LBM = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2. For females: LBM = 0.252 × weight(kg) + 0.473 × height(cm) − 48.3. Other formulas include James and Hume, which give slightly different results.
What is a healthy lean body mass percentage?
LBM percentage = 100% − body fat percentage. For men, a LBM of 80–90% (body fat 10–20%) is generally healthy. For women, 65–80% LBM (body fat 20–35%) is typical for healthy fitness levels. Elite athletes can have LBM above 90% for men and above 80% for women.