Muscle Mass (LBM) Calculator
Estimate your Lean Body Mass (LBM) and Body Fat using the Boer Formula.
Body Composition Breakdown
Lean Body Mass (LBM)
Estimated Fat Mass
Lean Body Mass includes your bones, organs, muscle, and water. This is an estimate using the Boer Formula. For exact medical measurements, a DEXA scan is required.
Skeletal Muscle Mass Standards & Medical References
NIH Clinical BenchmarkSkeletal muscle index (SMI) estimations, Lee anthropometric formulas, and sarcopenia classification adhere to NIH and European Working Group on Sarcopenia (EWGSOP2) clinical criteria.
Frequently Asked Questions
Explore comprehensive answers, mathematical formulas, and helpful guidance for calculating your results.
How is Skeletal Muscle Mass (SMM) estimated from height and weight?
Anthropometric equations such as the Boer and Lee formulas estimate Lean Body Mass (LBM) and appendicular skeletal muscle mass using height, weight, age, and biological sex coefficients correlated against DEXA scans.
What is the difference between Lean Body Mass and Skeletal Muscle Mass?
Lean Body Mass (LBM) includes all non-fat tissue (bones, organs, blood, water, and muscle), whereas Skeletal Muscle Mass (SMM) refers specifically to voluntary striated muscle tissue, typically accounting for 45–55% of LBM.
What is Skeletal Muscle Index (SMI) in sarcopenia screening?
Skeletal Muscle Index (SMI) normalizes skeletal muscle mass by height squared (kg/m²). EWGSOP2 clinical guidelines use SMI cutoffs alongside grip strength to screen for age-related sarcopenia.
How can I accurately track changes in muscle mass over time?
Measure weight and waist circumference under consistent morning hydration conditions, and pair anthropometric LBM estimates with progressive resistance training logs or bioelectrical impedance analysis (BIA).