How this calculator works
Enter the values for value, rate (%) and review the units before calculating.
Formula / method
Lean mass = body weight × (1 − body fat ÷ 100)
Worked example
70 kg at 20% body fat gives an estimated 56 kg lean body mass.
Assumptions and limitations
Body-fat percentage is an estimate and is measured consistently.
Lean mass includes water, organs, bone and muscle; this is not a diagnosis or a target weight.
Sources and methodology references
Informational only: this estimate is not medical advice and does not diagnose conditions.