This lean body mass calculator estimates your fat-free mass — everything except body fat — from your weight, height, and sex using the Boer formula. Enter your details above.
Formula (Boer)
Men: LBM = 0.407×W + 0.267×H − 19.2 Women: LBM = 0.252×W + 0.473×H − 48.3
- W — weight (kg), H — height (cm)
Example
Man, 80 kg, 180 cm: LBM = 61.4 kg.
Important
This tool is for general educational purposes only and is not medical advice, diagnosis, or treatment. It does not replace evaluation by a qualified healthcare professional — consult one for any health decision. Last updated: August 2026.
Frequently Asked Questions
What is lean body mass?
Your total weight minus body fat — muscle, bone, organs, and water. It helps guide nutrition and some drug dosing.
How do I calculate lean body mass?
The Boer formula uses weight, height, and sex. Other formulas (James, Hume) give similar estimates.
Why does lean body mass matter?
It relates to strength and metabolism, and clinicians use it to dose certain medications.