Calculate fat-free mass index and normalised FFMI from your weight, height and body fat percentage.
How the ffmi calculator works
FFMI measures how much lean mass you carry relative to your height, which BMI cannot distinguish from fat. It is the standard way of comparing muscularity between people of different sizes.
The normalised version adjusts to a 1.8 metre reference height so that tall and short lifters can be compared directly. Values around 25 and above are widely discussed as being at or beyond what is typically reached without pharmaceutical assistance, though individual genetics vary.
Using the calculator
- Enter your weight and height.
- Enter your body fat percentage — use the body fat calculator if you need it.
- Read your FFMI and the normalised figure.
The formula
Try it with these numbers
On the values this calculator opens with, the FFMI is 21.5. Underneath, Normalised FFMI comes out at 21.6 and Lean body mass at 68 kg. Change any field and every figure updates as you type.