Lean body mass calculator
Your lean body mass from height and weight, with three common formulas.
About this calculator
This lean body mass calculator estimates how much of your weight is not fat: muscle, bone, organs and water. Enter your sex, height and weight.
It compares three formulas used in medicine and fitness.
How it works
Lean body mass is everything except fat: muscle, bone, organs and water. The Boer formula for men is 0.407 × weight + 0.267 × height − 19.2, and for women 0.252 × weight + 0.473 × height − 48.3 (kg and cm).
Last reviewed:
Worked example
- Units: Feet and pounds
- Sex: Female
- Height: 5 ft 7 in
- Weight: 155 lb
Lean body mass: 110 lb (Boer formula)
Common questions
Why does lean body mass matter?
It's a better guide than total weight to how much energy you burn, and doctors use it to dose some medicines. It's also used to set protein targets.
How accurate are these formulas?
They estimate from height and weight only, so very muscular or very lean people can be off. A body scan or skinfold test measures it more directly.
How can I increase lean body mass?
Strength training with enough protein and sleep. Losing fat while keeping muscle also raises your lean share of body weight.
The story behind it
Where the idea came from: Doctors use lean body mass to dose some medicines, because many drugs spread mainly through lean tissue rather than fat.
The Hume formula of 1966, the James formula of 1976 and the Boer formula of 1984 were all written for medical use. They are now used in fitness too, for example in the Katch-McArdle equation for daily calories.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, not medical advice.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
Meet the founder