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Fat-Free Mass Index (FFMI) Calculator
Calculate Fat-Free Mass Index (FFMI), normalized height adjustments, and assess natural genetic muscularity potential.
About Fat-Free Mass Index (FFMI)
FFMI measures muscularity scaled to skeletal frame height, widely applied in athletic profiling to assess natural muscular development.
Formulas
- Fat-Free Mass (FFM): Weight × [1 - (Body Fat / 100)]
- Raw FFMI: FFM (kg) / [Height (m)]2
- Normalized FFMI: Raw FFMI + 6.1 × [1.8 - Height (m)]
Frequently Asked Questions
What is the typical natural ceiling for normalized FFMI?
Classic anthropometric studies (Kouri et al.) observed an approximate upper natural ceiling near 25.0 in drug-free athletes.
What does an average untrained male FFMI measure?
An average untrained male typically registers an FFMI around 18.0 to 19.5; trained natural lifters often reach 21.5 to 23.5.
Why normalize for height?
Taller athletes naturally carry higher absolute lean mass; normalization adjusts values against a standard 1.8-meter frame.
Can female athletes use this scale?
Yes, though baseline reference ranges are lower. Natural female athletes generally reach maximum levels around 18.0 to 20.0.
How to use
Calculate in three steps
- 1Enter your valuesUse the fields above and check the units shown beside each input.
- 2Run the calculationSelect Calculate to refresh the result with your latest values.
- 3Review or shareCompare the result, reset the form, print it, or share this page.
Inputs
What you need
Height (cm)cm
Weight (kg)kg
Body Fat Percentage (%)%