Body tool
Lean body mass calculator
Lean body mass (LBM) is your total weight minus your fat mass — muscle, bone, organs and water. This calculator estimates it from your weight, height and sex using the Boer formula, and shows your fat mass too.
- Fat mass
- 19.1 kg
- Approx. body fat
- 23.9%
Everything that isn't fat — muscle, bone, organs and water. An estimate; the trend matters most.
The basics
What is Lean Body Mass?
Lean body mass (LBM) is everything in your body that isn't fat — muscle, bone, organs and water. Knowing it helps set protein targets and track whether you're keeping muscle while losing fat. We use the Boer formula, a well-regarded estimate from your weight, height and sex.
How to use it
- 1Pick your sex. The Boer formula differs for men and women.
- 2Enter weight & height. Input your current weight and height.
- 3Read your LBM. Your estimated lean body mass and fat mass appear instantly.
FAQ
Lean Body Mass Calculator — questions
How do I calculate lean body mass?
The Boer formula estimates it from weight and height: for men, LBM = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2; for women, 0.252 × weight + 0.473 × height − 48.3. This calculator does the maths for you.
Why does lean body mass matter?
It shows how much of your weight is muscle and other lean tissue. Tracking it during a diet tells you whether you're losing fat (good) or muscle (bad), and it helps set an accurate protein target.
Put it to work
Turn your number into a plan
A calculator gives you a number. Coaching turns it into a programme that adapts to your data — start with the guide and the matching programme.
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