🦾 FFMI Calculator
Fat-free mass index and your muscle category
About this calculator
The Fat-Free Mass Index measures how much muscle you carry relative to your height, which makes it far more useful than BMI for anyone who trains. It divides your lean mass by your height squared, then normalizes for height so tall and short lifters can be compared. Natural lifters rarely exceed 25, which makes it a popular reality check.
Tip: Your body fat estimate is the weak link here. A DEXA scan or a skilled caliper measurement beats a bathroom scale's guess by a wide margin.