Free tool

FFMI Calculator

Measure muscle development with the Fat-Free Mass Index. See how close you or your clients are to the natural muscle-building ceiling and set realistic goals backed by the Kouri et al. (1995) study.

What is FFMI?

The Fat-Free Mass Index is a metric that scores muscle development relative to height. Unlike BMI, it accounts for real body composition, making it far more useful for anyone who lifts.

Units

If you don't know your body fat percentage, use a body fat calculator or estimate visually (typical ranges: men 10-25%, women 18-35%).

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Frequently asked questions