💪 Lean Body Mass Calculator

Lean body mass is your total body weight minus body fat. It includes muscles, bones, organs, and water. LBM is a better indicator of health and fitness than total body weight because it distinguishes between fat and non-fat mass.

This calculator uses the Boer formula, which is considered one of the most accurate prediction equations for lean body mass. However, it's still an estimate. For precise measurements, consider DEXA scans, hydrostatic weighing, or bioelectrical impedance analysis.

To increase LBM, focus on resistance training (weightlifting), consume adequate protein (0.7-1g per pound of body weight), maintain a slight caloric surplus, get sufficient sleep (7-9 hours), and stay consistent with your training program. Progressive overload is key to muscle growth.

Lean body mass includes all non-fat tissue: muscles, bones, organs, and water. Muscle mass refers specifically to skeletal muscle tissue. LBM is typically 40-50% muscle mass, with the rest being bones, organs, and fluids. You cannot directly measure muscle mass without specialized equipment.

Yes, lean body mass naturally decreases with age, a condition called sarcopenia. Adults can lose 3-8% of muscle mass per decade after age 30, and the rate increases after 60. Regular resistance training and adequate protein intake can help slow or prevent this loss.

Measure your LBM every 4-6 weeks if you're actively trying to change body composition. More frequent measurements aren't useful because significant changes in lean mass take time. Always measure under similar conditions (same time of day, hydration level) for consistency.