FFMI Calculator
FFMI calculator: find your fat-free mass index and normalized FFMI from weight, height and body fat percentage.
Editorial review: Farrow (pseudonym; identity and professional credentials are not disclosed). This page is for educational purposes, not professional advice.
Updated
Your inputs
Results update as you type. Nothing you enter leaves your device.
Results
- FFMI
- 22
- Lean mass
- 153 lb
- Rating
- Above average
Example with the starting values
These results use the calculator's initial inputs. Change the values above to calculate your own estimate.
Inputs
- Weight
- 180 lb
- Height
- 70 in
- Body fat
- 15 %
Results
- Normalized FFMI
- 22.1
- FFMI
- 22
- Lean mass
- 153 lb
- Rating
- Above average
How does the FFMI Calculator work?
Lean mass is body weight times (1 - body fat). FFMI is lean mass in kilograms divided by height in meters squared.
Normalized FFMI adds 6.1 x (1.8 - height in meters) so tall and short people compare fairly. Around 25 is near the natural upper range.
Frequently asked questions
What is a good FFMI?
Men commonly fall between 18 and 22. Values near 25 are rare without drug use.
How is FFMI different from BMI?
FFMI removes fat mass, so muscular people are not mislabeled overweight.
How accurate is the body fat input?
Estimates from scales or calipers can be off by several points, which moves FFMI.
Is FFMI useful for women?
The formula works, but typical ranges are lower for women. Compare against female reference ranges.