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Lean body mass calculator
Choose a direct calculation from a body-fat percentage you already have, or an estimate from the published Boer height-and-weight equation. See the method and assumptions.
Estimated lean body mass
Formula used:
Estimates vary by method and person. The Boer equation is a population regression, not a direct measurement. Adult estimate only; not for children or pregnancy and not medical advice. Ask a qualified clinician about health decisions.
How do I calculate lean body mass?
If you know a body-fat percentage, lean mass is body weight multiplied by one minus that percentage. Otherwise, the Boer estimate uses a sex-specific equation with weight and height. Results are estimates, not a body-composition measurement.
Frequently asked questions
How do I calculate lean body mass?
If you know a body-fat percentage, lean mass is body weight multiplied by one minus that percentage. Otherwise, the Boer estimate uses a sex-specific equation with weight and height. Results are estimates, not a body-composition measurement.
Is this lean body mass calculator private?
Yes. The calculation runs in your browser. Your weight, height and body-fat entry are not uploaded or saved.
What is the difference between lean mass and fat mass?
This calculator treats lean mass as body weight minus estimated fat mass for the selected method. It does not measure muscle alone or separate every tissue component.
What does the Boer equation estimate?
It estimates lean body mass from height and weight using a published equation set for men or women. It can differ from an individual measurement, so treat it as a rough estimate.
Can I use this result as medical advice?
No. The result is an estimate and is not a diagnosis or treatment recommendation. It is intended for adults, not children or pregnancy. Ask a qualified healthcare professional about personal health decisions.