body composition
Lean body mass calculator
What is lean body mass?
Lean body mass (LBM) is the weight of everything in your body that is not fat — muscle, bone, organs, and water. It is the foundation of metabolic rate: more lean mass means a higher BMR and more calories burned at rest.
How to use this calculator
- Enter your weight, body fat percentage, height, and sex.
- Click Calculate LBM to see your lean mass, fat mass, and ideal body weight estimates from three formulas.
- Use the body fat calculator if you don't know your body fat percentage.
The formulas
Lean body mass
LBM = weight × (1 − body fat % / 100)
Ideal body weight — Hamwi
Male: 48 kg + 2.7 kg per inch over 5 ft
Female: 45.5 kg + 2.2 kg per inch over 5 ft
Ideal body weight — Devine
Male: 50 kg + 2.3 kg per inch over 5 ft
Female: 45.5 kg + 2.3 kg per inch over 5 ft
Ideal body weight — Robinson
Male: 52 kg + 1.9 kg per inch over 5 ft
Female: 49 kg + 1.7 kg per inch over 5 ft
How to interpret your result
Ideal body weight formulas were developed for clinical use and don't account for muscle mass. For trained athletes, LBM is more useful than ideal weight. Use LBM as the basis for protein targets (2.2 g/kg LBM is a reliable starting point).
Related tools
- Body Fat % Calculator — estimate your body fat percentage
- TDEE Calculator — calculate daily calorie needs
Read more
What is lean body mass?
Lean body mass (LBM) is the weight of everything in your body that is not fat — muscle, bone, organs, and water. It is the foundation of metabolic rate: more lean mass means a higher BMR and more calories burned at rest.
How to use this calculator
- Enter your weight, body fat percentage, height, and sex.
- Click Calculate LBM to see your lean mass, fat mass, and ideal body weight estimates from three formulas.
- Use the body fat calculator if you don't know your body fat percentage.
The formulas
Lean body mass
LBM = weight × (1 − body fat % / 100)
Ideal body weight — Hamwi
Male: 48 kg + 2.7 kg per inch over 5 ft
Female: 45.5 kg + 2.2 kg per inch over 5 ft
Ideal body weight — Devine
Male: 50 kg + 2.3 kg per inch over 5 ft
Female: 45.5 kg + 2.3 kg per inch over 5 ft
Ideal body weight — Robinson
Male: 52 kg + 1.9 kg per inch over 5 ft
Female: 49 kg + 1.7 kg per inch over 5 ft
How to interpret your result
Ideal body weight formulas were developed for clinical use and don't account for muscle mass. For trained athletes, LBM is more useful than ideal weight. Use LBM as the basis for protein targets (2.2 g/kg LBM is a reliable starting point).
Related tools
- Body Fat % Calculator — estimate your body fat percentage
- TDEE Calculator — calculate daily calorie needs
Frequently asked questions
What is lean body mass?
Lean body mass is everything in your body except fat — muscle, bone, organs, and water. It is the best reference for setting protein targets and calorie needs.
What is the difference between LBM and ideal body weight?
LBM is what you already have in non-fat mass. Ideal body weight is a reference target based on height and frame. The Hamwi, Devine, and Robinson formulas estimate ideal body weight, not LBM directly.
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