Lean Body Mass Calculator
What Is Lean Body Mass (LBM)?
Lean Body Mass (LBM) is everything in your body but fat. It encompasses muscles, bones, organs, blood, skin, connective tissue, and water. Another way to put it is your body weight minus your body fat weight.
While LBM is not typically calculated as a percent, it usually accounts for 60% to 90% of an individual’s entire weight. Males tend to have a higher percentage of LBM than females based on differing amounts of muscle mass and fat distribution.
In clinical environments, LBM is significant. To provide an example, certain medications most notably those that are water-soluble are prescribed based on a patient’s lean body mass. It is utilized in some diagnostic tests as well. For fitness and general health monitoring, however, individuals are more interested in body fat percentage than lean mass.
While LBM is not typically calculated as a percent, it usually accounts for 60% to 90% of an individual’s entire weight. Males tend to have a higher percentage of LBM than females based on differing amounts of muscle mass and fat distribution.
In clinical environments, LBM is significant. To provide an example, certain medications most notably those that are water-soluble are prescribed based on a patient’s lean body mass. It is utilized in some diagnostic tests as well. For fitness and general health monitoring, however, individuals are more interested in body fat percentage than lean mass.
Formulas Used to Estimate Lean Body Mass (eLBM)
A number of formulas have been created to calculate lean body mass from your weight (in kilograms) and height (in centimeters). The most popular equations are:
eLBM = 0.407 × weight + 0.267 × height – 19.2
Women:
eLBM = 0.252 × weight + 0.473 × height – 48.3
Men:
Women:
eLBM = 0.32810 × weight + 0.33929 × height – 29.5336
Women:
eLBM = 0.29569 × weight + 0.41813 × height – 43.2933
These equations are commonly used in the clinical and research environment to approximate LBM when direct measuring tools such as DXA scans are not readily accessible.
1. Boer Formula
Men:eLBM = 0.407 × weight + 0.267 × height – 19.2
Women:
eLBM = 0.252 × weight + 0.473 × height – 48.3
2. James Formula
Men:
eLBM = 1.1 × weight – 128 × ( weight height )2
Women:
eLBM = 1.07 × weight – 148 × ( weight height )2
3. Hume Formula
Men:eLBM = 0.32810 × weight + 0.33929 × height – 29.5336
Women:
eLBM = 0.29569 × weight + 0.41813 × height – 43.2933
These equations are commonly used in the clinical and research environment to approximate LBM when direct measuring tools such as DXA scans are not readily accessible.
Lean Body Mass in Children
For kids, particularly those between 13 and 14 or younger, the Peters Formula is usually employed. It approximates lean body mass through extracellular fluid volume:
Approximate extracellular volume (eECV):
eLBM = 3.8 × eECV
Once more, weight is in kilograms and height is in centimeters.
Approximate extracellular volume (eECV):
eECV = 0.0215 × weight0.6469 × height0.7236
Determine eLBM:eLBM = 3.8 × eECV
Once more, weight is in kilograms and height is in centimeters.
Lean Body Mass vs. Fat-Free Mass: What's the Difference?
The phrases lean body mass (LBM) and fat-free mass (FFM) are usually used interchangeably, yet they differ.
- Lean Body Mass consists of everything in your body apart from stored fat, yet includes essential fat present in organs such as your brain, liver, and kidneys.
- Fat-Free Mass eliminates all fat, even including the essential fat present in your organs.
- For men, LBM is approximately 2–3% greater than FFM.