FFMI calculator
Fat-free mass index is the lifter's version of BMI: how much muscle you carry for your height, with fat taken out. Enter your numbers for the raw and normalized score and where it sits against the natural range.
How FFMI is calculated
Fat-free mass is your body weight minus fat mass. FFMI divides that by height squared, exactly like BMI. The normalized score adds 6.1 × (1.8 m − your height) so tall and short people are compared on the same scale.
What the numbers mean
- Under 18 — little muscle mass, or very lean with a small frame.
- 18–20 — average, untrained to lightly trained.
- 20–22 — visibly muscular; usually a year or more of proper training.
- 22–25 — advanced natural. Kouri, Pope, Katz and Oliva (1995) found the drug-free athletes they measured topped out around 25.
- Over 25–26 — outside the range they observed without steroids, or a body-fat estimate that is too low.
The catch
FFMI is only as good as your body-fat estimate. A five-point error in body fat moves the score by more than a full point. Use a consistent method, and treat the bands as a rough map rather than a verdict.
From a number to a picture
FFMI tells you roughly how far you are from your natural ceiling. LiftLooks shows you what that ceiling looks like on your own frame: upload one photo, pick Genetic maximum, and get a before/after in about a minute. Or run the natural limit calculator first for the weight version of the same question.
Now see it on your body.
Get the app, upload one photo, and see this transformation rendered on your own frame.
