This lean body mass calculator estimates how much of your weight is not fat: muscle, bone, organs and water. It uses two widely cited formulas, Boer and Hume, and works in metric or imperial units.
Lean body mass formulas
Boer (men): 0.407 × weight (kg) + 0.267 × height (cm) − 19.2
Boer (women): 0.252 × weight (kg) + 0.473 × height (cm) − 48.3
Hume (men): 0.32810 × weight + 0.33929 × height − 29.5336
Hume (women): 0.29569 × weight + 0.41813 × height − 43.2933
Worked example
A man who weighs 80 kg and is 180 cm tall has an estimated lean body mass of 61.4 kg by the Boer formula and 57.8 kg by Hume. The Boer result implies about 23% body fat.
Frequently asked questions
How accurate are these formulas?
They are estimates from population data. They can be off for very muscular people and for people with obesity. DEXA scans and other body composition tests are more accurate.
Why does lean body mass matter?
It is used to set protein targets, and some drug doses are based on it. See the protein calculator and body fat calculator.
For information only; not medical advice.