What is lean body mass?

Total weight minus fat mass. Includes muscles, bones, organs, skin, blood, and water. For men typically 75-85%, for women 65-75% of total weight.

Why is LBM important?

It determines protein needs (2-2.5g per kg LBM for athletes), metabolic rate, and whether you are losing fat or muscle during a diet.

Lean Body Mass Calculator

Calculate your fat-free mass (muscle, bone, water)

Lean Body Mass (LBM) is everything except fat. Muscles, bones, organs, water. Knowing your LBM sets accurate protein targets, tracks muscle gain, and reveals what your scale number really means.

Weight (kg)

Body Fat %

Don't know your body fat %? Try our body fat calculator.

How It Works

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Take or upload a photo for AI-powered body analysis.

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Our AI estimates body composition using visual analysis technology.

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Receive calculated results with detailed breakdown and recommendations.

Understanding Lean Body Mass

LBM is the most meaningful fitness metric. Each kg of muscle burns ~13 calories at rest vs ~4.5 for fat. More lean mass = higher metabolism = easier weight maintenance.