FFMI & Lean Body Mass Calculator

FFMI measures lean mass relative to height squared, so unlike BMI it is not distorted by muscularity. The normalised version adjusts to a 1.80 m reference height so lifters of different heights can be compared directly. A normalised FFMI around 25 is the widely cited upper bound for drug-free trained men, based on Kouri's analysis of pre-steroid-era bodybuilders. Worked example: a man who weighs 85 kg with 15% body fat has 72.25 kg of lean mass. At 1.80 m tall the FFMI is 72.25 ÷ 1.80² = 22.3, and because 1.80 m is the reference height the normalised value is also 22.3. Typical untrained men sit in the high teens to low 20s, and body fat estimates are themselves uncertain, so treat the result as a rough guide.