Your weight is not just fat and muscle. Break it down. All data stays in your browser.
Lean body mass is everything in your body that is not fat — muscle, bone, organs, skin, blood, and water. This calculator subtracts your fat mass from total weight to get lean mass, then breaks it down into estimated components. Muscle mass is derived by subtracting bone, organ, and skin/blood estimates from total lean mass. Bone mass is estimated from your height and sex using population averages. Organ mass uses reference ranges for brain, liver, heart, and kidneys. These are estimates, not DEXA-level precision, but they give you a useful picture of what your weight actually consists of.
Tip: Use this calculator after getting your body fat % from the Body Fat Estimator or a DEXA scan. Track lean mass over time — if it is going up while fat is stable, you are recomping successfully even if the scale does not move.
Watch your lean mass grow and fat mass shrink over time. Stored locally.
No saved calculations yet.
Get your body fat percentage first, then calculate lean mass.
Plan your timeline from current lean mass to goal.
Log measurements to track lean mass changes over time.