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Calculate your lean body mass, skeletal muscle weight, and fat-free mass using Boer, James, and Hume formulas.
Adjust the input parameters to calculate your results instantly.
| Scenario Inputs | Output Result |
|---|---|
| weight : 70, bodyFat : 20 | Lean Body Mass: 56.00 kg (80%), Body Fat Mass: 14.00 kg (20%) |
Lean Body Mass (LBM) Calculator. Calculate your lean body mass, skeletal muscle weight, and fat-free mass using Boer, James, and Hume formulas. ZechKit provides this tool completely free and online, optimized for instant, accurate computations directly inside your web browser.
Lean Body Mass (LBM) represents total body weight minus adipose fat tissue—encompassing skeletal muscle, bones, organs, connective tissue, and bodily fluids.
Formulas: Boer Formula (Men: LBM = 0.407W + 0.267H − 19.2; Women: LBM = 0.252W + 0.473H − 48.3, with W in kg and H in cm). James Formula (Men: LBM = 1.1W − 128(W/H)²; Women: LBM = 1.07W − 148(W/H)²).
Metabolic Role: Lean body mass is the primary driver of basal metabolic rate; preserving LBM during calorie-restricted diets keeps metabolism elevated.
Protein Nutrition: Nutritional guidelines recommend setting daily protein intake relative to lean body mass (e.g., 1.6 to 2.2 grams of protein per kilogram of LBM) to support muscle maintenance.
