Body Composition
Fat mass from lean mass
Whatever is not lean is fat. Dividing this by total weight gives body fat as a proportion.
The Formula
fatMass = W - LBM
Whatever is not lean is fat. Dividing this by total weight gives body fat as a proportion.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| W | Weight | kilograms | Total body weight. |
| LBM | Lean body mass | kilograms | Estimated lean mass. |
| F | Fat mass | kilograms | The remainder. |
What Each Symbol Means
Wkilograms
Weight
Total body weight.
LBMkilograms
Lean body mass
Estimated lean mass.
Fkilograms
Fat mass
The remainder.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate lean body mass page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Lean Body Mass, filed under Health. Every number the guide produces comes from substituting into this one line.