Lean Body Mass Calculator

Estimate how much of your weight is not fat (muscle, bone, organs and water).

Units
Fractions and decimals both work.
–
Lean body mass
Boer (1984)
James (1976)
Hume (1966)
From body fat %
Implied body fat (Boer)
Work

Saved Calculations

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Lean Body Mass Formulas

Boer: men 0.407W + 0.267H − 19.2; women 0.252W + 0.473H − 48.3
James: men 1.1W − 128(W/H)²; women 1.07W − 148(W/H)²
Hume: men 0.32810W + 0.33929H − 29.5336; women 0.29569W + 0.41813H − 43.2933

W in kg, H in cm. With a measured body fat %, lean mass = weight × (1 − body fat %).

Worked Example

Tips

The James formula gives odd results for very high BMIs. Formulas are population averages; a DEXA scan or other body-composition test is more accurate for one person.