Lean Body Mass Calculator

Lean Body Mass (LBM) represents all non-fat components of the body, including:

• Muscles
• Bones
• Organs
• Blood
• Connective tissue
• Essential lipids (within organs)

Key Characteristics:

• Typically constitutes 60-90% of total body weight
• Men generally have higher LBM percentages than women
• Crucial for medical applications (anesthesia dosing, diagnostic tests)
• Less commonly tracked than body fat percentage for fitness purposes

Calculation Formulas:

For Adults:

1. Boer Formula
   • Male: 0.407W + 0.267H - 19.2
   • Female: 0.252W + 0.473H - 48.3
2. James Formula
   • Male: 1.1W - 128(W/H)²
   • Female: 1.07W - 148(W/H)²
3. Hume Formula
   • Male: 0.32810W + 0.33929H - 29.5336
   • Female: 0.29569W + 0.41813H - 43.2933

For Children (≤14 years):
Peters Formula:
eLBM = 3.8 × (0.0215·W⁰·⁶⁴⁶⁹·H⁰·⁷²³⁶)

Where:
W = weight in kg
H = height in cm

Important Distinctions:

LBM vs. Fat-Free Mass (FFM):

Clinical Applications:

• Anesthesia dosing (especially water-soluble drugs)
• Nutritional assessment
• Metabolic rate calculations
• Monitoring body composition changes

References:

1. Boer (1984) – Physiological normalization index
2. James (1976) – Obesity research standards
3. Hume (1966) – Pathological applications
4. Peters et al. (2011) – Pediatric adaptations

For comprehensive body composition analysis, consider pairing with our Body Fat Calculator or Ideal Weight Calculator.