Lean Body Mass Calculator
Calculate your Lean Body Mass (LBM) using multiple validated formulas. Determine your fat-free mass for fitness and health planning.
Body Composition
Lean Body Mass
135.6 lbs
75.3% of body weight
Body Composition
Lean Body Mass
135.6 lbs
75.3% of body weight
Basic Information
Measurements
Body Composition
135.6 lbs
75.3% of body weight
44.4 lbs
24.7% of body weight
Formula Comparison
| Formula | LBM | Body Fat % |
|---|---|---|
| Boer | 135.6 lbs | 24.7% |
| James | 138.5 lbs | 23.1% |
| Hume | 126.9 lbs | 29.5% |
| Peters | 132.0 lbs | 26.7% |
Average LBM: 133.2 lbs
What Lean Body Mass Includes
Muscles
40-50%
Bones
15%
Organs
10-15%
Water & Blood
20-25%
Quick Answer
Lean Body Mass = Total Weight - Fat Mass. LBM includes muscle, bone, organs, and water. Boer formula (men): 0.407×weight(kg) + 0.267×height(cm) - 19.2. Average LBM: 60-90% of body weight.
Key Facts
- LBM = everything except fat
- Includes muscle, bone, organs, water
- Multiple estimation formulas exist
- Higher LBM = higher metabolism
- Preserving LBM important during weight loss
- Athletes have higher LBM percentage
Frequently Asked Questions
Lean Body Mass is your total body weight minus fat mass. It includes muscles, bones, organs, skin, blood, and water. LBM is important for determining metabolic rate, medication dosing, and fitness goals. Higher LBM generally indicates better metabolic health.
LBM is estimated using formulas based on height and weight. Common formulas include Boer (most accurate for average adults), James (good for both genders), and Hume (validated in clinical settings). Each uses different coefficients but relies on the same inputs.
Healthy LBM varies by gender. Men typically have 75-85% LBM (15-25% body fat). Women typically have 65-75% LBM (25-35% body fat) due to essential fat differences. Athletes may have higher LBM percentages.
Increase LBM through resistance training, adequate protein intake (0.7-1g per pound of bodyweight), progressive overload, and sufficient recovery. Focus on compound exercises like squats, deadlifts, and presses. Maintain a slight caloric surplus for muscle gain.
Each formula was developed using different populations and methodologies. Boer is considered most accurate for average adults. James works well across genders. Hume was validated in clinical settings. Use the average or the formula most suited to your demographics.
Body Composition
Lean Body Mass
135.6 lbs
75.3% of body weight
Medical Disclaimer
This calculator is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making any health-related decisions.