FFMI calculator guide
FFMI measures how much lean mass you carry for your height — a far better muscularity number than BMI. How to read the scale.
1 min read
Written & reviewed by Ricardo Tapia·Last updated
FFMI (Fat-Free Mass Index) measures how much lean mass you carry for your height — a far better "how muscular am I?" number than BMI, because it removes fat from the equation.
The math
fat-free mass = weight × (1 − body-fat % ÷ 100)
FFMI = fat-free mass ÷ height(m)²
Normalized FFMI adjusts the result to a 1.8 m reference so heights compare fairly.
Reading the scale (men)
| FFMI | Meaning |
|---|---|
| 16–18 | Below average |
| 18–20 | Average |
| 20–22 | Above average |
| 22–23 | Excellent |
| 23–26 | Superior |
| 26+ | Suspicious / unlikely natural |
The natural ceiling sits around 25.
You need an accurate body-fat % for this to mean anything — estimate it with the body-fat calculator first. Women's ranges run a few points lower.
Try it
Run your numbers in the FFMI calculator.
Sources & references
- Kouri EM, Pope HG, Katz DL, Oliva P. Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clin J Sport Med. 1995;5(4):223-228.
Educational content only. Not medical advice — consult a professional for your situation.