Lean Body Mass (LBM) is your total body weight minus fat mass - it includes muscle, bone, organs, and water, and is a useful benchmark for tracking fitness progress.
This calculator uses the Boer formula, one of the most commonly cited equations for estimating lean body mass from height, weight, and gender.
Example: A man, 175 cm tall, 75 kg:
LBM = 0.407×75 + 0.267×175 - 19.2 = 30.5 + 46.7 - 19.2 = 58.0 kg
Tracking LBM alongside weight helps you see whether changes on the scale come from muscle or fat, which is more meaningful for fitness goals.
It's a well-regarded estimate for the general population, though methods like DEXA scans give more precise, individual results.
Resistance training combined with adequate protein intake is the most effective way to build and maintain lean mass.