Lean Body Mass Calculator

Lean body mass (LBM) is the weight of your body minus all the fat. It includes muscles, bones, organs, skin, blood, and everything else that is not fat. It is sometimes called fat-free mass.

LBM determines your resting metabolic rate, strength, and functional capacity. Higher LBM means higher calorie burn at rest, better blood sugar regulation, and improved overall health outcomes.

Lean body mass includes all non-fat tissue: muscles, bones, organs, and water. Muscle mass refers specifically to skeletal muscle. LBM is always greater than muscle mass.

Yes. Resistance training (weight lifting) is the most effective way to increase lean body mass by building muscle. Adequate protein intake (1.6-2.2g per kg) is essential for muscle protein synthesis.

During weight loss, some lean body mass may be lost alongside fat, especially in crash diets. A high-protein diet combined with resistance training helps preserve lean mass while losing fat.

Sex, age, genetics, training history, nutrition, and hormonal factors all influence lean body mass. Men naturally have higher LBM than women. LBM declines with age (sarcopenia) but can be slowed with exercise.