Estimating skeletal muscle mass from height and weight
Skeletal muscle — the muscle attached to your bones that you can deliberately train and grow — makes up roughly half of total lean body mass in most adults. This calculator builds on the Boer lean body mass formula and applies a typical skeletal-muscle proportion to estimate the muscle component specifically, rather than all lean tissue.
It's worth being clear-eyed about the limits here: this is a population-average estimate, not a tissue-level measurement. Someone with an unusually high or low muscle-to-lean-mass ratio — a powerlifter versus someone recovering from prolonged bed rest, for example — will see a less accurate result than someone closer to typical body composition.
Why track this over time
The real value of a muscle mass estimate isn't the absolute number on day one — it's the trend across weeks and months of training. If your weight is stable but your estimated muscle mass is trending up, that's a good signal your training and protein intake are working in the right direction, regardless of how precise the underlying formula is in absolute terms.