Health & Fitness
Lean Body Mass Calculator
Estimate your lean body mass — everything that is not fat — and your fat mass from your height, weight and sex, using the Boer, James and Hume formulas.
cm
kg
Lean body mass
56.0 kg
about 80% of your body weight (Boer)
Lean mass
56.0 kg
Fat mass
14.0 kg
By formula
How to use the lean body mass calculator
Choose your sex and units and enter your height and weight. The calculator shows your estimated lean body mass (everything that is not fat), your fat mass, and what each of the three formulas gives. If you already know your body fat percentage, that route is more precise — use the Body Fat Calculator first.
The Boer formula
Men: LBM = 0.407·kg + 0.267·cm − 19.2
Women: LBM = 0.252·kg + 0.473·cm − 48.3
Example. A man of 175 cm and 70 kg has a lean body mass of about 56 kg by the Boer formula — roughly 80% of his weight — leaving about 14 kg of fat mass.
Frequently asked questions
Lean body mass (LBM) is the weight of everything in your body that is not fat — muscle, bone, organs, water and connective tissue. The rest is fat mass. For most adults lean mass is roughly 70–90% of total body weight.