FFMI Calculator
Calculate Fat-Free Mass Index from height, weight and body-fat percentage. See normalized FFMI, lean mass, fat mass and a strength-oriented category with all formulas running client-side.
Enter height
Use metric or imperial height so FFMI can normalize lean mass to your frame.
Add weight and body fat
The calculator separates fat-free mass from total body fat using your body-fat estimate.
Review FFMI level
See FFMI, normalized FFMI, fat-free mass and the category that matches your score.
FFMI inputs
FFMI score visual
Secondary metrics
What If Simulator
FFMI reference ranges
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FFMI Calculator FAQ
What is FFMI?
FFMI is Fat-Free Mass Index. It compares your lean mass to your height, similar to BMI but using fat-free mass instead of total body weight.
What is normalized FFMI?
Normalized FFMI adjusts the score to a reference height of 1.8 m, making comparisons fairer across different heights.
How accurate is this calculator?
The formulas are deterministic, but the result depends heavily on your body-fat estimate. DEXA scans, skinfolds, BIA scales and visual estimates can all produce different body-fat percentages.
This calculator is for education and fitness planning only. It is not medical advice and does not diagnose health, performance potential or drug use.
Results are estimates generated locally in your browser from standard formulas and general population data. They are for informational purposes only and do not constitute medical advice. Always consult a qualified healthcare or fitness professional before making changes to your training, diet or health plan. VisionVix accepts no liability for decisions made based on this tool's output.
