About the Lean Body Mass Calculator
What is the Lean Body Mass Calculator?
Lean body mass is everything in your body except fat: muscle, bone, organs and water. It drives your metabolism and is used for some drug doses and protein targets.
The calculator estimates it with three established formulas. If you know your body fat percentage, it uses that for a more direct result.
How to use the Lean Body Mass Calculator
- Sex (sample: Male)
- Weight (kg) (sample: 75)
- Height (cm) (sample: 172)
- Body Fat % if Known (0 to estimate) (sample: 0)
- Press Calculate Lean Body Mass (results also refresh as you type). The result card shows the Lean Body Mass, along with Method, Implied body fat, Boer formula and James formula.
Formula used
Boer: Men 0.407W + 0.267H − 19.2; Women 0.252W + 0.473H − 48.3
- W, H = weight in kg and height in cm
- From body fat = LBM = weight × (1 − body fat %)
Formulas are population averages; muscular people may have more lean mass than predicted.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Sex | Male |
| Weight (kg) | 75 |
| Height (cm) | 172 |
| Body Fat % if Known (0 to estimate) | 0 |
| Result | Value |
|---|---|
| Lean Body Mass | 57.2 kg |
| Method | Boer formula |
| Implied body fat | 23.7% |
| Boer formula | 57.2 kg |
| James formula | 58.2 kg |
| Hume formula | 53.4 kg |
Tips for using the Lean Body Mass Calculator
- Preserve lean mass while losing weight by eating enough protein and doing strength training.
- Use lean mass, not total weight, to set protein targets if you carry a lot of fat.