FFMI Calculator
Calculate your Fat-Free Mass Index to assess muscular development
What is FFMI?
Fat-Free Mass Index (FFMI) is a measure of muscular development that accounts for height. Unlike BMI, FFMI focuses on lean tissue, making it useful for assessing how much muscle someone has relative to their frame.
FFMI Formulas
FFMI = Fat-Free Mass / Height²Adjusted FFMI = FFMI + 6.1 × (1.8 - Height)How to Interpret Your FFMI
| FFMI Range | Classification |
|---|---|
| < 18 | Below Average |
| 18 - 19.9 | Average |
| 20 - 21.9 | Above Average |
| 22 - 22.9 | Excellent |
| 23 - 25.9 | Superior |
| ≥ 26 | Likely Enhanced |
Why Use FFMI?
FFMI is valuable because BMI penalizes muscular individuals. Someone with significant muscle mass might have a 'overweight' BMI despite low body fat. FFMI separates lean mass from fat, giving a better picture of physique composition.
Limitations
- Requires accurate body fat measurement
- Natural limits vary by genetics
- Less meaningful for those not strength training