Lean Body Mass Calculator — Calculate Your LBM

Lean Body Mass Calculator

Calculate your lean body mass (LBM) using different formulas. Estimate muscle mass, body fat percentage, and track your fitness progress.

Step 1: Personal Information

Male
Female
Metric Imperial
kg
cm
years
%

What is Lean Body Mass?

Lean Body Mass (LBM) is the total weight of your body minus all the weight due to your fat mass. It includes muscles, bones, organs, and water. Knowing your LBM helps track fitness progress and calculate proper nutrition needs.

Step 2: Calculation Options

LBM Formulas

Boer Formula: Most accurate for athletes
James Formula: Common for general population
Hume Formula: Good for older adults
Simple Formula: LBM = Weight × (1 – Body Fat % / 100)

Lean Body Mass Results

Body Composition
Formula Comparison
Interpretation

Your Lean Body Mass

56.0 kg
Male, 30 years, 70 kg, 175 cm
Body Fat Percentage
20.0%
Fat Mass
14.0 kg
Lean Body Mass (lbs)
123.5 lbs
BMI
22.9

Formula Comparison

Formula Lean Body Mass Body Fat % Fat Mass Accuracy

About the Formulas

Boer Formula: Developed in 1984, most accurate for athletes and active individuals
James Formula: Published in 1976, suitable for general population
Hume Formula: Created in 1966, tends to be more accurate for older adults
Simple Formula: Requires body fat percentage input, most personalized when accurate body fat data is available

Lean Body Mass Interpretation Guide

Male Lean Body Mass Ranges (kg)

Essential Fat 2-5% body fat
Athletes 6-13% body fat
Fitness 14-17% body fat
Average 18-24% body fat
Obese 25%+ body fat

Female Lean Body Mass Ranges (kg)

Essential Fat 10-13% body fat
Athletes 14-20% body fat
Fitness 21-24% body fat
Average 25-31% body fat
Obese 32%+ body fat

Why Lean Body Mass Matters

Lean body mass is crucial for:

  • Metabolism: Muscle burns more calories at rest than fat
  • Strength & Function: Supports daily activities and athletic performance
  • Bone Health: Resistance training increases bone density
  • Longevity: Higher muscle mass is associated with longer lifespan
  • Disease Prevention: Reduces risk of diabetes, heart disease, and osteoporosis

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