FFMI Calculator
Find your Fat-Free Mass Index (FFMI) and estimate your lean muscle mass limits and category.
| Lean Muscle Mass | 154.8 lbs (70.2 kg) |
| Total Fat Mass | 25.2 lbs (11.4 kg) |
The Mathematics of FFMI Calculations
FFMI (Fat-Free Mass Index) acts as an alternative to BMI (Body Mass Index) for bodybuilders and athletes because BMI does not distinguish between muscle mass and fat tissue. FFMI isolates your lean body mass relative to your height.
The FFMI Equation:
FFMI = Lean Mass (kg) / Height (meters)^2
The Normalized FFMI Equation:
Because taller individuals naturally hold more skeletal frames, the Normalized FFMI adjusts your score to standard 1.8-meter metrics (5'11"):
Frequently Asked Questions
Scientific studies of natural athletes indicate a general natural ceiling of approximately 25 FFMI for males. An FFMI score between 25 and 28 is exceptionally rare naturally, and scores above 28 are highly indicative of anabolic steroid usage.
For this calculator, you can estimate your body fat using standard skin caliper measurements, bioelectrical impedance scales, a DXA scan, or the US Navy Body Fat circumferential formula.