IBM (Lean Body Mass) Calculator
Result
The lean body mass based on different formulas
| Formula | Lean Body Mass | Body Fat |
| Peters (for Children)4 | - | - |
| Boer1 | - | - |
| James2 | - | - |
| Hume3 | - | - |
IBM Calculator (Lean Body Mass) Formula
Lean Body Mass Formulas for Adults
The Boer Formula:1 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: | |||||||
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| For females: | |||||||
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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
Lean body mass and fat free mass are often used interchangeably. While this is unlikely to cause issues in most cases, the two are not exactly the same.
Lean body mass includes the combined mass of bones, muscles, water, ligaments, tendons, and internal organs. Internal organs include some essential fat and the mass of this fat is included within the measurement of lean body mass. Although internal organs also have surrounding subcutaneous fat, this fat is not included within the measurement of lean body mass.
Fat free mass is calculated as the difference between total body mass and all fat mass including essential fat. This is the difference between fat free mass and lean body mass. Subtracting the mass of essential fat from lean body mass yields fat free mass. The difference between lean body mass and fat free mass amounts to approximately a 2-3% difference in men and 5-12% difference in women.