Lean Body Mass Calculator
Lean body mass (LBM) is your total weight minus fat — including muscle, bone, organs, and water. This calculator uses the Boer formula to estimate your LBM from weight, height, and sex.
How it works
This calculator uses the Boer formula, a widely used equation for estimating lean body mass from total weight and height. For males: LBM = (0.407 × weight kg) + (0.267 × height cm) − 19.2. For females: LBM = (0.252 × weight kg) + (0.473 × height cm) − 48.3.
Fat mass is calculated as total weight minus lean body mass, and body fat percentage is fat mass divided by total weight, times 100. These are estimates based on population averages, not direct measurements.
Tips
LBM is useful for setting protein targets, dosing certain medications, and tracking changes from training. For more accuracy, compare formula estimates with a DEXA scan or bioelectrical impedance reading.
Because the Boer formula is height- and weight-based, very muscular or very lean individuals may see results that differ from measured values — use it as a guideline, not a clinical figure.
FAQ
What is lean body mass?
Lean body mass is everything in your body that isn't fat — muscle, bone, organs, connective tissue, and water. It's your total weight minus your fat mass.
Which formula does this use?
It uses the Boer formula, which estimates LBM from weight and height with separate equations for males and females. It's one of the most commonly cited formulas in clinical and fitness settings.
How accurate is the estimate?
It's a reasonable estimate for average body types but can be off for athletes or very lean people. For precise figures, use a DEXA scan, hydrostatic weighing, or bioimpedance device.