Lean Body Mass Calculator
Estimate your lean body mass (everything except fat) and your body fat from your height and weight, using the Boer formula.
Lean body mass
60.1 kg
- Lean share of your weight
- 75.11%
- Estimated body fat
- 19.9 kg (24.9%)
About 60.1 kg of your 80 kg is lean mass: muscle, bone, organs and water.
How it's worked out
- Boer formula
0.407 × 80 + 0.267 × 175 − 19.260.1 kg
- A height-and-weight estimate; it can't tell a muscular person from one carrying more fat. The body fat calculator's tape-measure method is closer for most people.
The Boer formula
Men: 0.407W + 0.267H − 19.2 · Women: 0.252W + 0.473H − 48.3
Worked example
A man of 80 kg and 175 cm: 32.56 + 46.73 − 19.2 = 60.1 kg of lean mass, leaving about 19.9 kg (24.9%) of fat.
Questions people ask
What is lean body mass?
Everything in the body except fat: muscle, bone, organs, skin and water.
What is the Boer formula?
For men, 0.407 × weight + 0.267 × height − 19.2; for women, 0.252 × weight + 0.473 × height − 48.3 (kg and cm).
Why does lean body mass matter?
It's used to dose some medicines and set protein targets, and keeping it up while losing weight means losing fat rather than muscle.
About this calculator
Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem