FFMI calculator
FFMI (fat-free mass index) measures how much lean mass you carry relative to your height — a better muscle gauge than BMI. Enter weight, height and body-fat %. A normalised FFMI around 25 is near the natural ceiling for men; women sit lower.
- Lean (fat-free) mass
- 68 kg
- Raw FFMI
- 21.5
Most drug-free lifters sit 18–23; ~25 is near the natural ceiling for men, lower for women.
What is FFMI?
Fat-Free Mass Index (FFMI) is your lean (fat-free) mass in kilograms divided by your height in metres squared, then normalised to a 1.8 m frame. Unlike BMI it ignores fat, so it reflects muscularity. Drug-free men rarely exceed a normalised FFMI of about 25; most lifters land between 18 and 23. It's only as accurate as the body-fat figure you put in.
How to use it
- 1Enter weight and height. Input your bodyweight in kilograms and height in centimetres.
- 2Enter body fat. Add your estimated body-fat percentage — use our body-fat calculator if unsure.
- 3Read your FFMI. Your normalised FFMI and muscularity band are calculated instantly.
FFMI Calculator — questions
What is a good FFMI?
Most trained, drug-free men sit between 18 and 23. A normalised FFMI around 25 is widely cited as the approximate natural ceiling; women typically range a few points lower.
Is FFMI better than BMI?
For lifters, yes — FFMI ignores fat and reflects how much muscle you carry for your height, whereas BMI counts muscle and fat the same and can mislabel a muscular person as overweight.
How accurate is FFMI?
It's only as accurate as your body-fat estimate, since lean mass is derived from it. Track the trend with a consistent body-fat method rather than fixating on a single reading.
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