FFMI Calculator
Measure your muscularity with the fat-free mass index.
BMI for muscle
FFMI does for muscle what BMI does for weight: it scales your fat-free mass to your height so you can gauge muscularity on a standard scale. It needs your weight, height, and body-fat percentage.
An 80 kg, 180 cm lifter at 15% body fat has about 68 kg of lean mass and an FFMI near 21 — a solid, achievable natural level. The normalized value adjusts for height so results compare fairly across body sizes.
Clear and private
It computes lean mass and both index values in your browser, so nothing you enter is uploaded.
Frequently Asked Questions
What is FFMI?
Fat-free mass index — your lean mass divided by height squared, like BMI but for muscle. It gauges how muscular you are independent of fat.
What values are typical?
Untrained men sit around 18 to 20; well-trained natural lifters reach the low-to-mid 20s. Values much above 25 are rare without enhancement.
What is the normalized value?
An adjustment that scales FFMI to a standard height so tall and short people can be compared fairly.
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