Estimate your lean body mass and fat mass from your height, weight and sex, using the Boer formula.
How the lean body mass calculator works
Lean body mass is your total weight minus body fat — muscle, bone, organs and water. Enter your details and this calculator estimates it with the Boer formula.
It’s an estimate; methods like DEXA scans measure it more precisely.
Try it with these numbers
On the values this calculator opens with, the lean body mass is 56. Underneath, Body fat mass comes out at 14 kg and LBM % of weight at 80%. Change any field and every figure updates as you type.
Step by step
- Choose your sex.
- Enter your height and weight.
- Read your lean body mass and fat mass.
How the number is calculated
Boer (men) = 0.407×kg + 0.267×cm − 19.2
women = 0.252×kg + 0.473×cm − 48.3
Frequently asked questions
What is lean body mass?
Everything in your body that isn’t fat — muscle, bone, organs and water. It’s useful for tracking body composition.
Why does it matter?
Preserving lean mass while losing fat is a common fitness goal, and some medication doses are based on it.
How accurate is the formula?
Formulas estimate from height, weight and sex only, so they’re approximate. Scans give precise figures.