ðĶī Lean Body Mass Calculator
Calculate your fat-free body mass
How it works
Calculate your lean body mass (everything except fat) using the Boer, James, and Hume formulas. Know exactly how much of your weight is muscle, bone, water, and organs vs fat. Essential for tracking body composition changes during cuts or bulks.
Disclaimer: This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.
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Frequently Asked Questions
- What is lean body mass and why does it matter?
- Lean body mass is your total body weight minus all fat mass, including muscles, bones, organs, water, and connective tissue. It is a more useful metric than total weight for assessing fitness because two people at the same weight can have very different body compositions. Higher lean mass is associated with a faster metabolism, better insulin sensitivity, and greater functional strength.
- How does the Boer formula calculate lean body mass?
- The Boer formula estimates lean body mass using your height and weight with sex-specific coefficients. For men the formula is 0.407 times weight in kg plus 0.267 times height in cm minus 19.2, and for women it is 0.252 times weight plus 0.473 times height minus 48.3. It is one of the most validated estimation formulas and performs well across a wide range of body types.
- How can I increase my lean body mass?
- Progressive resistance training combined with adequate protein intake (1.6 to 2.2 grams per kilogram of body weight) is the most effective way to increase lean mass. Prioritize compound movements like squats, deadlifts, and presses, and ensure you are eating at or slightly above maintenance calories. Consistent training over months and years produces the most significant and sustainable gains.