FFMI Index

The Genetic Limit.

The Fat-Free Mass Index (FFMI) is the ultimate metric for muscle mass, accounting for both weight and body fat. Find out where you stand on the spectrum of human muscular potential.

FFMI Calculator

Fat-Free Mass Index — a better gauge of muscularity than BMI.

Use the Navy Body Fat Calculator if you don't already know this.

Disclaimer: This tool is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Your Results

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Normalized FFMI (adjusted to 6ft / 1.83m for comparison)
Fat-Free Mass
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For men, a normalized FFMI above ~25 is rare without performance-enhancing drugs; most genetically-typical, well-trained natural lifters top out around 22-25. The natural ceiling for women is roughly 4-5 points lower. Treat this as a rough benchmark, not a verdict.