Lean Body Mass Calculator

Lean Body Mass Calculator

Formula Lean Body Mass Body Fat

What is Lean Body Mass?

  • Definition:
    • Lean body mass (LBM) represents the weight of your body if it were completely devoid of any body fat.
    • This includes organs, bones, muscles, blood, skin, and everything else that has mass and is not fat.
  • Importance in Weight Loss:
    • Monitoring Muscle Loss: Monitoring your LBM is crucial when trying to lose weight. It helps you track how much muscle you might be losing.
    • Dietary Impact: Solely losing muscle can lead to disappointing results and an unpleasant appearance.
    • Decision Making: Understanding your LBM aids in determining how much fat you should lose and projecting your body fat percentage after weight loss.
  • Accuracy Over Body Weight:
    • Calculating your LBM provides a more accurate assessment of your physical composition than just considering overall body weight.

Lean Body Mass Formulas for Adults

The Boer Formula:1

For males:
eLBM = 0.407W + 0.267H – 19.2
For females:
eLBM = 0.252W + 0.473H – 48.3

The James Formula:2

For males:
eLBM = 1.1W – 128(W/H)^2
For females:
eLBM = 1.07W – 148(W/H)^2

The Hume Formula:3

For males:
eLBM = 0.32810W + 0.33929H – 29.5336
For females:
eLBM = 0.29569W + 0.41813H – 43.2933

Lean Body Mass Formula for Children

The Peters Formula:4

The author suggests that this formula is applicable for children aged 13-14 years old or younger. The formula is used to compute an eLBM based on an estimated extracellular volume (eECV) as follows:

eECV = 0.0215·W0.6469·H0.7236
eLBM = 3.8·eECV

In the formulas above, W is the body weight in kilogram and H is the body height in centimeter.

Lean Body Mass vs. Fat Free Mass

AspectLean Body MassFat-Free Mass
DefinitionLean body mass includes the combined mass of bones, muscles, water, ligaments, tendons, and internal organs.Fat-free mass is the total body mass minus all fat mass, including essential fat.
ComponentsLean Body Mass includes: Bones, Muscles, Water, Ligaments, Tendons, Internal organs (along with some essential fat)Fat-Free Mass consists of: All components of Lean Body Mass, Excludes any kind of fat, including essential fat
Essential FatIncludes the mass of essential fat found in internal organs.Does not include the mass of essential fat.
Subcutaneous FatDoes not include surrounding subcutaneous fat of internal organs.Excludes subcutaneous fat as well as essential fat.
MeasurementMeasured by including the essential fat found in internal organs.Measured by subtracting all fat mass, including essential fat, from total body mass.
Difference in MassSlightly higher due to the inclusion of essential fat.Slightly lower when compared to lean body mass, as it excludes essential fat.
Percentage DifferenceApproximately 2-3% higher in men and 5-12% higher in women when compared to fat-free mass, due to the inclusion of essential fat in internal organs.
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