Health & Fitness Calculators
Lean Body Mass Calculator
Estimate your lean (fat-free) body mass.
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About the Lean Body Mass Calculator
Lean body mass (LBM) is everything in your body except fat — muscle, bone, organs, and water. Enter your sex, height, and weight and the calculator uses the Boer formula to estimate your lean mass and fat mass. It's useful for setting protein needs, tracking recomposition, and understanding weight changes beyond the scale.
How to use the Lean Body Mass Calculator
- 01Enter your sex, height, and weight.
- 02Read the result instantly — it recalculates as you type.
- 03Adjust the numbers to model different scenarios.
Frequently asked questions
What is lean body mass?
Your total weight minus fat mass — muscle, bone, organs, and water. It's the part of you that burns most of your calories.
Why does LBM matter?
More lean mass raises your metabolic rate and strength. Protein intake is often set per kilogram of lean mass.