Lean Body Mass Calculator
Estimate fat-free mass (LBM) using Boer, Hume, and James formulas. Useful for protein-intake targets and tracking body recomposition.
HEALTHEstimate fat-free mass (muscle, bone, organs, water — everything except fat) using three established formulas: Boer, Hume, and James. Useful for setting protein targets and tracking body recomposition.
Boer: best general accuracy for adults. Hume: developed for clinical use, similar accuracy. James: simpler, less precise for very tall or short people. The three are averaged for a robust point estimate. Multiply LBM by 1.6-2.2 g/kg to get a recomp/lean-bulk protein target.
Lean Body Mass Calculator
Estimate fat-free mass (muscle, bone, organs, water - everything except fat) using three established formulas. Useful for setting protein-intake targets and tracking recomposition progress.
Anthropometric LBM estimates are accurate to ±5-10% for typical adults. They under-estimate for very muscular people (because the formulas assume average body composition for given height/weight) and over-estimate for sedentary people. For higher accuracy, use DEXA scan, BodPod, hydrostatic weighing, or 3-site/7-site skinfold caliper measurements.