FFMI Calculator
FFMI is BMI for muscle: it strips out fat so you can see how muscular you are for your height.
About this tool
Fat-free mass index equals lean mass divided by height squared. Normalised FFMI adjusts to a 1.8 m reference height. A 1995 study of male bodybuilders (Kouri et al.) reported that natural athletes rarely exceeded about 25; average untrained men sit around 18-20.
Body fat estimates drive the result, so treat FFMI as a rough gauge. Use a DEXA or careful skinfold reading for the best inputs.
How to read your result
18-20 average, 20-22 above average, 22-23.5 excellent, 25 near the natural ceiling.
Run about 3-4 points lower.
Frequently asked questions
Does an FFMI above 25 mean steroids?
This tool is for information and education only and is not medical advice. For adults 18 and over. Read the full disclaimer.
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