What is FFMI?

FFMI (Fat Free Mass Index) measures lean body mass relative to height squared, like BMI but for muscle FFM (kg) / [height (m)]². It doesn't adjust for height variations, so taller people may score lower despite similar muscularity.

Normalized FFMI refines this by scaling to an average height of 1.8m Normalized FFMI = FFMI + 6.1 × (1.8 height in m). This ensures fairer comparisons across heights.

For average height, they're identical otherwise, it boosts scores for taller folks or reduces for shorter ones.

You can find our FFMI calculator here, FFMI calculator

It will calculate for you both normalized and raw FFMI.

For more detailed info on FFMI, see this guide: Genetic ceiling of Muscle Gain