FFMI Calculator
Fat free mass index with the height-normalised adjustment.
Enter your values
ⓘ Live results
Results
- Adjusted FFMI
- 21.58
- Raw FFMI
- 21.46
- Lean body mass
- 68 kg
- Fat mass
- 12 kg
- Rating
- above average
Working
- 1lean 68 kg / 1.78^2 = 21.46
- 2adjusted = 21.46 + 6.1 x (1.8 - 1.78) = 21.58
Quick answer
FFMI is lean mass in kilograms divided by height in metres squared. It rates muscularity independently of fat, and around 25 adjusted is the usual natural ceiling.
FFMI = lean kg / height m^2; adjusted = FFMI + 6.1 x (1.8 - height m)
How to use the FFMI Calculator
- 1Enter your weight and height, then your best body fat estimate (calipers, DEXA or a scan).
- 2Read the adjusted FFMI, which corrects for being taller or shorter than 1.8 m.
- 3Track it over months — FFMI moving up while body fat holds flat means real muscle gain.
Worked example
Using the values the calculator loads with:
Inputs
- Body weight80 kg
- Height178 cm
- Body fat15 %
Results
- Adjusted FFMI21.58
- Raw FFMI21.46
- Lean body mass68 kg
- Fat mass12 kg
- Ratingabove average
- lean 68 kg / 1.78^2 = 21.46
- adjusted = 21.46 + 6.1 x (1.8 - 1.78) = 21.58
Frequently asked questions
What FFMI is achievable naturally?
Most drug-free lifters top out around 22 to 25 adjusted FFMI. Values above 26 are uncommon without exceptional genetics.
Why does body fat accuracy matter so much?
FFMI is driven entirely by lean mass, so a body fat estimate that is 5 points off will shift FFMI by roughly one full point.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.