FFMI Calculator
Determine your Fat-Free Mass Index (FFMI)
What is FFMI?
FFMI stands for Fat-Free Mass Index, which allows you to calculate the amount of muscle mass relative to height. This index is similar to BMI (Body Mass Index) but takes into account body composition by excluding fat mass.
The FFMI was created by researchers to identify potential steroid use in bodybuilders. It's a useful metric for anyone looking to track muscle gains while accounting for differences in height.
FFMI Formula
Total Body Fat = Weight * (Body fat % / 100)
Lean Mass = Weight * (1 - Body fat % / 100)
FFMI = Lean Mass / (Height in m)²
Adjusted FFMI = FFMI + [6.1 * (1.8 - Height in m)]
FFMI Interpretation
The calculated normalized FFMI can be interpreted using the table below. You also need to consider your body fat percentage and normal muscle mass for your gender.
Generally, an FFMI above 25 is considered to be at the upper limit of what can be achieved naturally for men, though this can vary based on genetics and other factors.
FFMI Score for Men
| FFMI | Body Fat | Description |
|---|---|---|
| 17-18 | 10-15% | Skinny/Lean |
| 18-20 | 10-15% | Average male |
| 20-22 | 10-15% | Fit male |
| 22-23 | 10-15% | Above average/Intermediate gym user |
| 23-25 | 8-12% | Advanced gym user |
| 25-27 | 8-10% | Exceptional/Professional/Potential PED |
| 27+ | 7-9% | Elite/Professional/Likely PED |
FFMI Score for Women
| FFMI | Body Fat | Description |
|---|---|---|
| 14-15 | 20-22% | Skinny woman |
| 15-16 | 22-24% | Average female |
| 16-18 | 20-22% | Fit female |
| 18-19 | 18-20% | Above average/Intermediate gym user |
| 19-20 | 16-18% | Advanced gym user |
| 20-22 | 14-16% | Exceptional/Professional/Potential PED |
| 22+ | 12-14% | Elite/Professional/Likely PED |
How to Use FFMI
To calculate your FFMI, complete the following simple steps:
- Choose the measurement system (metric or imperial)
- Enter your height
- Enter your weight
- Enter your body fat percentage
- Click the "Calculate" button to get the results
Note: For the most accurate FFMI calculation, you should have a reliable body fat percentage measurement. This can be obtained through methods like DEXA scan, BodPod, hydrostatic weighing, or a professional skinfold caliper test.