What does Lean Body Mass (LBM) include?

LBM includes everything in your body except subcutaneous and visceral fat. It represents the weight of your skeletal muscle, bones, vital organs, blood, and water content.

Why is LBM important for physical fitness?

Knowing your LBM is essential for tailoring protein targets, planning caloric intake, and tracking actual fat-loss progress without being deceived by standard bathroom scales.

How is fat weight calculated from LBM?

Fat Weight = Total Weight - Lean Body Mass. For example, if you weigh 200 lbs and your LBM is 160 lbs, you have 40 lbs of fat weight.

Health Tool

Lean Body Mass Calculator

Calculate your Lean Body Mass (LBM) using the Boer, James, and Hume formulas. Find your exact body composition of muscle and fat weight.

Interactive Lean Body Mass Calculator Workspace

Live Solver

Body Weight (kg)

Height (cm)

Lean Body Mass Projections

Boer Formula58.0 kgStandard recommendation

James Formula59.0 kgTraditional reference

Hume Formula54.4 kgAlternate weight curve

Calculated Fat Mass17.0 kg

Estimated Body Fat %22.6%

Mathematical Formula & Variables

Equation ModelLBM (Boer Male) = 0.407 * weight_kg + 0.267 * height_cm - 19.2

Lean Body Mass represents total body weight minus adipose fat tissue. It is calculated using formulas that weigh height against body mass.

Variable Definitions

Symbol	Description
LBM	Lean Body Mass in kilograms
weight_kg	Body weight in kilograms
height_cm	Vertical height in centimeters

How to Use the Lean Body Mass Calculator

Choose Metric or Imperial units.
Select biological sex.
Enter weight and height.
Calculate to view LBM estimates, fat weight, and corresponding skeletal composition ratios.

Practical Example Calculation

Scenario Context: Calculating LBM using Boer formula for a female weighing 65 kg who stands 165 cm tall.

Step 1: Multiply weight by 0.252 female Boer coefficient: 65 * 0.252 = 16.38.

Step 2: Multiply height by 0.473 female Boer coefficient: 165 * 0.473 = 78.045.

Step 3: Subtract female Boer constant (48.3): 16.38 + 78.045 - 48.3 = 46.125.

The Boer Lean Body Mass estimate is 46.1 kg.

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