Lean Body Mass Calculator

Estimate your lean body mass.

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Lean Body Mass (LBM) Results
Based on different common formulas.

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A Guide to Lean Body Mass (LBM)

Lean Body Mass (LBM) represents the total weight of your body minus all the weight due to fat mass. It is a crucial component of your body composition and includes the weight of your bones, muscles, organs, skin, and water. Understanding your LBM is often more insightful for assessing health and fitness than looking at total body weight alone.

Why LBM Matters

  • Metabolic Rate: Muscle tissue is more metabolically active than fat tissue. A higher LBM means you burn more calories at rest (a higher Basal Metabolic Rate).
  • Fitness Tracking: When you're on a fitness journey, the scale can be misleading. You might be gaining muscle and losing fat, but your total weight might not change much. Tracking LBM helps you see the positive changes in your body composition.
  • Clinical Applications: In medicine, LBM is used to determine appropriate dosages for certain medications, as many drugs are distributed in non-fatty tissues.

How LBM is Calculated

The most accurate way to determine LBM is through advanced imaging like a DEXA scan. However, several mathematical formulas have been developed to estimate LBM using simple body measurements. This calculator uses three common formulas:

  • The Boer Formula: A widely used formula developed in 1984.
  • The James Formula: Another popular method from 1976.
  • The Hume Formula: A well-regarded formula developed in 1966.

Each formula uses a slightly different equation based on weight, height, and gender, which is why they give slightly different results. They provide a reliable estimation without the need for a body fat percentage measurement. The calculator also estimates your body fat percentage based on the LBM result from the Boer formula, giving you a complete body composition snapshot.

Disclaimer: This calculator provides an estimation of lean body mass. The results are for educational purposes and are not a substitute for a professional medical assessment.

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A Guide to Lean Body Mass (LBM)

Lean Body Mass (LBM) represents the total weight of your body minus all the weight due to fat mass. It is a crucial component of your body composition and includes the weight of your bones, muscles, organs, skin, and water. Understanding your LBM is often more insightful for assessing health and fitness than looking at total body weight alone.

Why LBM Matters

  • Metabolic Rate: Muscle tissue is more metabolically active than fat tissue. A higher LBM means you burn more calories at rest (a higher Basal Metabolic Rate).
  • Fitness Tracking: When you're on a fitness journey, the scale can be misleading. You might be gaining muscle and losing fat, but your total weight might not change much. Tracking LBM helps you see the positive changes in your body composition.
  • Clinical Applications: In medicine, LBM is used to determine appropriate dosages for certain medications, as many drugs are distributed in non-fatty tissues.

How LBM is Calculated

The most accurate way to determine LBM is through advanced imaging like a DEXA scan. However, several mathematical formulas have been developed to estimate LBM using simple body measurements. This calculator uses three common formulas:

  • The Boer Formula: A widely used formula developed in 1984.
  • The James Formula: Another popular method from 1976.
  • The Hume Formula: A well-regarded formula developed in 1966.

Each formula uses a slightly different equation based on weight, height, and gender, which is why they give slightly different results. They provide a reliable estimation without the need for a body fat percentage measurement. The calculator also estimates your body fat percentage based on the LBM result from the Boer formula, giving you a complete body composition snapshot.

Disclaimer: This calculator provides an estimation of lean body mass. The results are for educational purposes and are not a substitute for a professional medical assessment.