Health
FFMI (Fat-Free Mass Index)
An index measuring muscle mass relative to height, calculated as (lean mass in kg) / (height in meters)^2. Used in fitness to assess muscularity; a natural upper limit is approximately 25 FFMI.
FFMI isolates lean tissue rather than total weight, so a muscular athlete who looks “overweight” by BMI reads accurately here. A normalized FFMI near 25 is often cited as the natural ceiling for drug-free trainees.
Key Formula & Relationship
FFMI = Fat-Free Mass (kg) / [Height (m)]²
Reviewed by the Calculover Editorial Team for mathematical and practical accuracy.
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