💪 Lean Body Mass Calculator
Lean body mass is your weight minus body fat — muscle, bone, organs and water. It is used in some dosing and nutrition calculations.
How the Lean Body Mass Calculator works
The calculator uses the Boer (1984) formula, one of the most widely used estimates. Body fat percentage is estimated as the rest of your weight.
Step-by-step calculation
- 1Enter weight, height and sex.
- 2Apply the Boer formula.
- 3Body fat % is the remaining weight.
Worked example
A man weighing 80 kg at 180 cm: LBM = 0.407 × 80 + 0.267 × 180 − 19.2 = 61.4 kg, which suggests about 23% body fat.
Lean Body Mass Calculator examples
| Weight | Lean body mass |
|---|---|
| 60 | 53.3 kg |
| 80 | 61.4 kg |
| 100 | 69.6 kg |
| 120 | 77.7 kg |
Other inputs kept at the calculator's default values. Results calculated by this calculator.
Why use a Lean Body Mass Calculator?
Estimate muscle and lean tissue for nutrition planning.
Important factors that can affect your results
- Formulas are estimates.
- Very muscular or older people.
- Hydration.
Frequently asked questions
How accurate is it?
Formulas give estimates. DEXA scans or other body composition tests are more accurate.
Can I use pounds and inches?
Yes — choose US units and the calculator converts them.
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Last reviewed November 2026 · How we build and check our tools · Report a problem