Lean Body Mass

Lean Body Mass Overview

Calculate LBM using Boer, James, and Hume formulas

The Lean Body Mass (LBM) Calculator estimates the weight of your body minus all fat content. This includes muscle, bone, water, and organs. Knowing your LBM is crucial for setting macronutrient goals—especially protein intake—and for anesthetic dosing in medical contexts. This tool uses three validated formulas (Boer, James, and Hume) to provide an accurate average estimate. It is an essential tool for bodybuilders tracking muscle growth and patients requiring precise medication dosages.

How to Use Lean Body Mass

Frequently Asked Questions

What is Lean Body Mass?
Lean Body Mass is everything in your body except fat. This includes your bones, organs, muscles, skin, and body water.
Is LBM the same as muscle mass?
Not exactly. LBM includes bone and water. However, changes in LBM usually reflect changes in muscle mass, assuming hydration is constant.
Which formula is best?
The Boer formula is most commonly used for people with normal body composition. The James formula is older. We provide an average of all three for the best estimate.

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