What is lean body mass?

Lean body mass (LBM) is total body weight minus fat mass. It includes muscles, bones, organs, and body water. LBM is used in drug dosing calculations and metabolic rate estimation.

How can I increase lean body mass?

Progressive resistance training combined with adequate protein intake (1.6–2.2g/kg) is the most effective way to increase lean body mass.

Lean Body Mass Calculator – Boer, James, Hume Formulas

Lean Body Mass Calculator

Calculate your lean body mass (LBM) using the Boer, James, and Hume formulas.

Units

Metric

Imperial

Sex

Male

Female

Weight (kg)

Height (cm)

Known body fat % (optional)

Lean Body Mass (avg)

60.0 kg

Body fat mass: 20.0 kg

Formula	LBM	Fat Mass
Boer (1984)	60.9 kg	19.1 kg
James (1976)	62.1 kg	17.9 kg
Hume (1966)	57.1 kg	22.9 kg

Lean Body Mass Calculator

Lean Body Mass (LBM) is total body weight minus fat mass. It includes muscle, bone, organs, blood, and water. It is important for calculating medication doses, protein targets, and body composition goals.

Formulas used

Boer (1984): Generally the most accurate for adults. Male: 0.407W + 0.267H − 19.2
James (1976): Common in critical care and anaesthesia dosing.
Hume (1966): Older formula, still widely referenced.

If you know your body fat percentage, enter it for the most accurate result — this bypasses all formula assumptions.