Lean Body Mass Calculator
Estimate your lean body mass (everything except fat) using three peer-reviewed formulas. Optionally enter your body fat percentage for a more accurate direct calculation.
Lean Body Mass
59.1 kg
Lean Body Mass
59.1 kg
73.9% of your body weight
Lean mass
59.1 kg
73.9%
Fat mass
20.9 kg
26.1%
Body composition
Formula comparison
What is lean body mass? LBM is everything in your body that isn't fat — muscles, bones, organs, water, and connective tissue. It's useful for calculating drug dosages, setting protein targets, and tracking body composition changes during fat loss. Unlike total weight, LBM tells you whether you're losing fat or muscle.
Sources: Boer (1984) "Estimated lean body mass as an index for normalization of body fluid volumes in humans"; James (1976) "Research on obesity", DHSS/MRC report; Hume (1966) "Prediction of lean body mass from height and weight", Journal of Clinical Pathology 19(4):389–391. If you know your body fat %, the direct method (LBM = weight × (1 − BF%/100)) is more accurate than any estimation formula.