Lean Body Mass Calculator

How Lean Body Mass is Calculated: The Formulas Behind the Tool

Our Lean Body Mass Calculator uses three well-established equations developed by researchers for clinical use. Here's how they work:

1. Boer Formula

• Men: LBM = (0.407 × weight) + (0.267 × height) - 19.2
• Women: LBM = (0.252 × weight) + (0.473 × height) - 48.3
• Units: weight in kg, height in cm
• Best for: Clinical accuracy in adults

2. James Formula

• Men: LBM = 1.1 × weight - 128 × (weight² / height²)
• Women: LBM = 1.07 × weight - 148 × (weight² / height²)
• Units: weight in kg, height in cm
• Note: May be inaccurate for people with high fat mass

3. Hume Formula

• Men: LBM = (0.32810 × weight) + (0.33929 × height) - 29.5336
• Women: LBM = (0.29569 × weight) + (0.41813 × height) - 43.2933
• Units: weight in kg, height in cm
• Used in: Pharmacokinetics and medical dosage calculations

Why Knowing Your Lean Body Mass Matters

Lean Body Mass (LBM) represents everything in your body except fat — including muscles, bones, water, and organs. It’s essential for:

• Tracking fat loss instead of just weight loss
• Designing personalized training and nutrition plans
• Calculating your Basal Metabolic Rate (BMR)
• Monitoring sarcopenia and other health conditions

Essential vs Storage Body Fat: Know the Difference

Not all body fat is created equal. Understanding the difference between essential fat and storage fat is key to setting realistic fitness and health goals.

Essential fat is necessary for basic body functions — especially in organs and hormone production. Storage fat, on the other hand, is the extra energy reserve that accumulates under your skin and around organs.