Lean Body Mass Calculator

Calculate your lean body mass (LBM) using the Boer formula. Find out how much of your weight is muscle, bone, and organ tissue.

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What Is Lean Body Mass?

Lean body mass (LBM) is the total weight of everything in your body except fat — including muscle, bone, organs, skin, and water. It is one of the most important metrics in fitness and clinical nutrition because it drives your basal metabolic rate, determines your strength potential, and reflects overall health quality independent of fat levels.

The Boer Formula

This calculator uses the Boer formula (1984), one of the most validated LBM equations for general adult populations:

Men: LBM = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2
Women: LBM = 0.252 × weight(kg) + 0.473 × height(cm) − 48.3

Why LBM Matters

Your LBM directly determines your basal metabolic rate. The more lean mass you carry, the more calories you burn at rest. Tracking LBM over time is more meaningful than tracking scale weight alone — you could lose fat and gain muscle while staying at the same weight, dramatically improving your health.

Frequently Asked Questions

What is a good lean body mass percentage?
Most healthy adults have an LBM of 70–90% of total body weight. Athletes tend to be at the higher end; women typically have slightly lower LBM percentages than men at the same weight.
How can I increase my lean body mass?
Progressive resistance training (weight lifting) combined with adequate protein intake (1.6–2.2g per kg of body weight) is the most effective strategy for building lean mass.
Is lean body mass the same as muscle mass?
No. LBM includes muscle, bone, organs, and water. Muscle mass is typically about 40–50% of total LBM.
Medical Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for health decisions.