Fat-Free Mass Index Calculator
Lean mass relative to height, normalised for comparison.
Your result
Normalised FFMI adjusts for height. Values around 20 are average for untrained adults; trained athletes often score higher.
Medical disclaimer: This tool is for education and is not medical advice. Read more.
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Frequently asked questions
What does the Fat-Free Mass Index Calculator do?
Lean mass relative to height, normalised for comparison. Enter your values and the result and chart update instantly.
How accurate is it?
It uses published, widely used formulas. Results are estimates for education and planning, not a diagnosis. Talk to a qualified clinician about decisions affecting your health.
Is my information stored or shared?
No. All calculations run in your browser and nothing you type is sent to a server or saved.
What can I search to find this tool?
People find it by searching for: ffmi calculator; natural muscle potential; lean mass index.