FFMI Calculator

18–20 is average; 20–22 is above average with visible training; 22–24 is excellent and typical of dedicated natural lifters; 25+ is exceptional.

15–17 is average; 17–18.5 above average; 18.5–20 excellent. Women's ranges sit several points below men's due to hormonal differences in muscle building.

The formula is exact, but it inherits your body fat measurement error. Home scale ±4–8%, calipers ±3%, DEXA ±1–2%. Track with one method over time rather than chasing point accuracy.

BMI counts muscle as if it were fat, flagging muscular people as overweight. FFMI subtracts fat mass first, so it measures what BMI cannot: how much lean tissue you carry.

Roughly. Studies of natural bodybuilders put typical ceilings around 24–25 FFMI for men; values above 26 are rare without enhancement. Genetics shift individual ceilings by a few points either way.

Every 4–8 weeks under matched conditions (morning, fasted if using scales, same device). Weekly readings add noise, not information.

Percentile charts exist but adult categories don't map to developing bodies. Teens should track strength and consistency rather than FFMI targets.

DEXA if available; otherwise consistent caliper landmarks or a reliable tape-based method (Navy formula). Avoid comparing readings across different methods.