Your measurements
Protein target at this bodyweight: — per day, the 1.6–2.2 g/kg range for resistance-trained individuals.
What FFMI measures
BMI divides your total mass by your height squared, which means it cannot tell muscle from fat. Every lifter who has ever been told they are “overweight” at 12% body fat has met the limitation directly.
FFMI does the same division but throws the fat away first: it is your fat-free mass divided by height in metres squared. Two people at the same weight and height get very different FFMIs if one is carrying ten kilos more muscle.
Why the normalised figure exists
The raw index still drifts with height — taller people tend to score slightly lower for the same build, because mass does not scale to the square of height in a real body. The normalised figure corrects toward a 1.80 m reference so that two people of different heights can be compared at all. It is the number worth tracking.
The input that decides everything
Before optimising anything, verify the instrument. If you are tracking FFMI over time, use the same estimation method every time and compare the trend rather than the absolute value — a consistently wrong method still shows the direction correctly, whereas switching methods between measurements tells you nothing at all.
What the number cannot tell you
FFMI is a descriptive index, not a verdict. It says nothing about how that lean mass is distributed — two lifters at an identical FFMI can look entirely different if one has built their back and shoulders and the other has not. It is a gauge for total tissue, not for proportion, and proportion is what is actually visible.
You will find FFMI cited as evidence of a hard natural ceiling. That claim rests on a small and much-argued dataset, so it is not made here. What the number is genuinely good for is watching your own trend across months.
How this is calculated
- Lean mass = bodyweight × (1 − body fat %)
- FFMI = lean mass ÷ height in metres, squared
- Normalised FFMI = FFMI + 6.1 × (1.8 − height in metres)
- Protein = 1.6 to 2.2 g per kg of bodyweight per day
This page calls the same engine the plan builder uses rather than reimplementing the formula, so the figure here and the figure in your spec sheet cannot disagree.
FFMI tells you how much. Not where.
The free spec sheet takes the same measurements and answers the more useful question: which muscle is currently limiting the rest, and what to do about it in week one.
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