Health Formula • Published on July 30, 2026 • Last updated July 30, 2026
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Body weight in kilograms
Height in centimeters
Lean Body Mass — total body weight minus fat mass (muscle, bone, organs, water)
Lean Body Mass represents everything in the body except fat.
The Boer formula estimates it directly from weight and height using gender-specific regression coefficients, without requiring a body fat percentage measurement.
It is commonly averaged together with other validated equations (James, Hume formulas) for a more robust estimate, and is useful for tracking muscle mass and setting nutrition targets independent of fat mass changes.
Boer, James, and Hume formulas were each derived from different population samples and regression approaches, so they can differ by a few kilograms for the same person — averaging multiple formulas helps reduce this individual variance.
No — Lean Body Mass includes muscle plus bone, organs, and body water, not muscle alone, so it is always higher than muscle mass by itself.
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