What is lean body mass?

Lean body mass includes everything except fat: muscle, bone, organs, water, and connective tissue. LBM = Total Weight × (1 - Body Fat%). A 180 lb person at 20% body fat has 144 lbs of LBM.

Why is LBM important for protein targets?

Protein targets based on LBM are more accurate than total body weight because protein supports muscle tissue, not fat. A standard recommendation is 1g protein per pound of LBM.

Can I improve LBM while losing weight?

Yes, particularly for beginners. Simultaneous fat loss and muscle gain ('body recomposition') is most achievable for those new to training, those returning after a break, or those with high initial body fat.

Lean Body Mass Calculator

Calculate lean body mass (LBM) from total body weight and body fat percentage. LBM = total weight minus fat mass. Used for accurate protein target setting, medication dosing, and tracking body composition changes during diet and exercise.

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How It Works

Each component has a specific meaning:

Body fat percentage — The body fat percentage recorded for the scenario being assessed.

Note: Interpret the lean body mass result against the thresholds and context described above.

How to Use

Enter the body fat percentage for the scenario you are assessing. Calculate lean body mass (LBM) from total body weight and body fat percentage. LBM = total weight minus fat mass. Used for accurate protein target setting, medication dosing, and tracking body composition changes during diet and exercise. Use the lean body mass result to inform your calculation.