Lean Body Mass Calculator

Lean Body Mass (LBM) = Total Weight - Fat Mass = Weight × (1 - body fat%). LBM includes muscles, bones, organs, water — ...

Guides & Reference

How It Works

Lean Body Mass (LBM) = Total Weight - Fat Mass = Weight × (1 - body fat%). LBM includes muscles, bones, organs, water — everything except fat. Used to set protein intake and calorie targets.

Quick Reference

80kg, 20% body fat

80 × (1-0.20)

LBM = 64kg

65kg, 25% body fat

65 × 0.75

LBM = 48.75kg

Protein per LBM

1g per lb LBM

Common guideline

Tips & Shortcuts

Protein goal: 0.7-1g per pound of lean body mass for muscle building.

Tracking LBM rather than weight shows muscle gain even when scale weight stays same.

LBM declines with age without strength training — muscle maintenance is critical.

Common Mistakes

Confusing LBM with muscle mass

LBM includes bones, organs, water, and muscle — not just muscle alone.

Setting calorie goals based on total weight instead of LBM

Calorie and protein needs scale with metabolically active tissue (LBM), not fat mass.

Frequently Asked Questions

Lean body mass (LBM) is your total weight minus body fat. It includes muscle, bone, organs, water, and connective tissue.

LBM determines your basal metabolic rate — muscle tissue burns more calories at rest than fat. Higher LBM means higher TDEE and easier weight management.

Progressive resistance training is the most effective method, paired with adequate protein (1.6–2.2g/kg) and maintenance or slight surplus calories.

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