Free FFMI Calculator Online
Determine your Fat-Free Mass Index (FFMI) and lean mass ratios based on height, weight, and body fat percentage.
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Fat-Free Mass Index muscle tracking
Track your athletic progress and lean muscle mass over time. Monitor your FFMI to evaluate hypertrophy programs and nutritional strategies.
Frequently Asked Questions (FAQ)
What is FFMI?
FFMI (Fat-Free Mass Index) is a fitness metric that estimates your muscle mass relative to your height. It is similar to BMI but accounts for body fat percentages.
What is a good FFMI score?
For natural lifters, an FFMI of 18-20 is average, 21-22 is excellent, and 23-25 is near the natural genetic limit. Scores above 25 are rarely achieved without anabolic assistance.
How is lean body mass calculated?
Lean Body Mass is your total body weight minus the weight of your body fat (Weight * (1 - Body Fat% / 100)).
Why normalize FFMI for height?
Taller lifters naturally have higher raw FFMI limits. Normalizing adjusts scores to a standard height of 1.8 meters for fair comparisons.
Is my physical data private?
Yes, FastCalc.tools operates entirely client-side and logs no user data.