Lean Body Mass Calculator
Estimate how much of your body weight comes from muscle, bone, and organs versus fat, using the widely used Boer formula.
What is lean body mass?
Lean body mass (LBM) is an estimate of everything in your body that isn’t fat: muscle, bone, organs, skin, and body water. It’s a useful reference point for tracking fitness progress or estimating nutrition needs, since muscle and fat behave very differently in the body.
How this calculator works
This tool uses the Boer formula, one of the most widely cited equations for estimating lean body mass from height, weight, and sex. It’s a population-based estimate rather than a direct measurement, so it works best as a general reference rather than an exact figure.
For a precise measurement of your body composition, methods like DEXA scans, bioelectrical impedance devices, or skinfold calipers performed by a trained professional are more accurate. This calculator is intended for general fitness planning and educational purposes only.