ffmi calculator
FFMI: how much muscle you carry for your height
Fat-free mass index is the lifter's version of BMI — total fat-free mass scaled by height, with a published normalization so tall and short people compare fairly. Enter your numbers (ideally from a DEXA report) and see where you sit against the published landmarks.
Last verified 2026-08-14
your fat-free mass index
21.2kg/m²
normalized to 1.80 m: 21.3 · fat-free mass 66.9 kg / 147 lb
against the published landmarks
In Kouri et al. 1995 — the paper that defined normalized FFMI — athletes who had not used steroids reached a well-defined ceiling around 25.0, and pre-steroid-era Mr. America winners averaged 25.4. Values above ~25 are rare without pharmacological help; most trained lifters live in the low 20s. Full context in the FFMI & ALMI guide.
Educational context, not a physique verdict — FFMI says nothing about performance, and its error is exactly the error of your body-fat estimate. Add your DEXA regional data in the full results interpreter for percentiles and ALMI.
Common questions
What is a good FFMI?
In the study that defined the metric (Kouri et al. 1995), athletes who had not used steroids reached normalized FFMI values up to a well-defined limit of about 25.0, and pre-steroid-era Mr. America winners averaged 25.4. Most untrained men sit in the high teens; trained lifters commonly reach the low 20s. Women's values run lower on average; the metric was defined in male samples, so treat female landmarks as less established.
What's the difference between FFMI and normalized FFMI?
Raw FFMI is fat-free mass divided by height squared. Kouri's group observed taller athletes score slightly lower, so they added a height correction: normalized FFMI = FFMI + 6.1 × (1.8 − height in meters). It lets people of different heights compare on one scale.
Why does the body-fat source matter so much?
FFMI inherits every percentage point of error in your body-fat estimate. With a DEXA value, FFMI is meaningful; with a smart-scale estimate that can be off by several points, your FFMI moves by roughly 0.2-0.3 per body-fat point of error. Same formula, very different confidence.
Is FFMI a natural-or-not detector?
No. The ~25 landmark describes the ceiling in one 1995 sample of 157 athletes; individuals vary, and FFMI says nothing about any specific person. It's context, not a verdict.
Want percentiles and ALMI too? The full results interpreter uses your DEXA regional data. The FFMI & ALMI guide covers where these indexes come from and their limits.