muscle mass calculator. Get instant, accurate results. Enter values for instant results with step-by-step formulas.
Reviewed for accuracy by Rahul Singh, Health & Wellness Specialist
Reviewed for accuracy by Rahul Singh, Health & Wellness Specialist
Medical disclaimer:
This calculator is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Results are general estimates and may not reflect your individual circumstances. Always consult a qualified healthcare professional before making decisions about your health.
Muscle Mass Calculator
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Formula: Lee Equation: SM(kg) = 0.244 x BW + 7.80 x Ht(m) - 0.098 x Age + 6.6 x Sex - 3.3 | LBM = Weight x (1 - BF%)
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Worked example — 31.9 kg muscle mass (42.5% of body weight)
Formula
Lee Equation: SM(kg) = 0.244 x BW + 7.80 x Ht(m) - 0.098 x Age + 6.6 x Sex - 3.3 | LBM = Weight x (1 - BF%)
The Lee equation estimates appendicular skeletal muscle mass from height, weight, age, and sex. Alternative: Lean Body Mass = total weight x (1 - body fat percentage). Average muscle mass: men 36-42% of body weight, women 29-35%.
Average skeletal muscle mass: men 36-42% of body weight, women 29-35%. Athletes may have 45-55%. Muscle mass declines 3-8% per decade after age 30 (sarcopenia).
What is the SMI threshold for sarcopenia?
Skeletal Muscle Index (SMI) = muscle mass / height². Low muscle mass: men <7.0 kg/m², women <5.4 kg/m² (per EWGSOP2 criteria). Also requires low strength or performance.
How can I increase muscle mass as I age?
Resistance training 2–4 times per week is the most effective intervention for preserving and building muscle mass at any age. Combine with adequate protein intake (1.6–2.0g/kg/day), sufficient calories, and quality sleep. Even older adults in their 70s and 80s can significantly increase muscle mass with progressive resistance training programs.
What is the difference between mass and weight?
Mass measures the amount of matter in an object (kilograms) and is constant everywhere. Weight is the gravitational force on that mass (newtons) and varies by location. On Earth, a 1 kg object weighs about 9.8 newtons. In everyday use, the terms are often used interchangeably.
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