FFMI calculator
Estimate the fat-free mass index and the normalized FFMI from weight, height and body fat percentage.
Normalized FFMI
21.1
Well-developed lean mass for the context entered.
Raw FFMI
20.8
Without adjustment for the reference height.
Fat-free mass
63.8 kg
Depends on the body fat percentage entered.
Correct reading
context
Doesn't predict a genetic ceiling or a future result.
FFMI shifts a lot if the body fat percentage is wrong. Use the number as context to track a trend, not as a verdict.
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Terms used in this calculator
These concepts show up in the math and help you read the result with more context.
- FFMI (fat-free mass index)
- FFMI relates fat-free mass to height to put lean mass in context beyond raw body weight.
- Fat-free mass
- Fat-free mass is the estimated body weight left after removing fat mass.
- Body fat percentage
- Body fat percentage estimates how much of your body weight comes from fat mass.
What FFMI shows
FFMI relates fat-free mass to height. It tries to put lean mass on a scale, instead of looking only at raw body weight.
The calculation depends directly on the body fat percentage you enter. If that percentage is wrong, the FFMI will be too. So read it as a contextual indicator.
No genetic-limit promise
The calculator doesn't define a maximum potential or classify what you can or can't reach. It shows a number to track context, history and trend.
In training, what you control is execution, progression, recovery and consistency. That's where SelfShapeAI works.
Sources and references
- Source: Kouri EM, Pope HG Jr, Katz DL, Oliva P. Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clin J Sport Med, 1995. — Clinical Journal of Sport Medicine (PubMed)
Reviewed by the SelfShapeAI research team.
Frequently asked questions
Is FFMI the same as BMI?
No. BMI uses total weight and height. FFMI uses estimated fat-free mass, so it depends on a reliable body fat percentage.
What is normalized FFMI for?
It adjusts FFMI to a reference height, making contextual comparison easier between people of different heights.
Does FFMI define my genetic potential?
No. The number can give context, but it doesn't predict an individual limit or replace real tracking of training and body composition.
Keep reading
Take the math into your training
SelfShapeAI builds the plan, logs your loads and adjusts volume with context — so you don't have to run the numbers by hand.
