Fat Free Mass Index (FFMI) Calculator

8th September 2016

fat free-mass-index calculator
You’ve probably heard about body mass index (BMI) but what about the fat-free mass index (FFMI)?

This tool factors in more than your weight, and takes into account muscle mass and fat mass as well. It is yet another great way to track your fat loss progress than just relying on the scale.

FFMI Calculator

Use this calculator to calculate your fat free Mass Index or FFMI.

Weight:   lbs
Bodyfat:   %
Height:  ft. in.
Lean:   lbs
Adjusted FFMI: 

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What is FFMI?

Many studies have been performed based upon Body Mass Index (BMI). While BMI is a decent indicator for the general population, it does not take into account muscle mass. BMI compares height to weight. Generally, when one person is heavier than another of the same height, they may have gained that weight from fat weight.

This becomes a negative health indicator. However, if that person is heavier due to muscle mass, they may actually be healthier, rending the BMI useless in their case! The FFMI is an index to take into account the amount of muscle mass a person is carrying and relate that to their height. It is not necessarily a superior index, but it does factor in different parameters than simply total weight.
A study of elite athlete (some admitted steroid users and some not) combined with an analysis of 20 Mr. America contest winners from the 1939-1959 pre-steroid era, determined that a fat free mass index of 25 is pretty much an upper limit for someone who does not use steroids. A fat free mass of 19 is the average for males.

Learn more about why fat free mass is a better way to track your fat loss and muscle building progress by clicking here!

If you are interested in the more common Body Mass Index then click here.


  • Schutz, Y., Kyle, U. U., & Pichard, C. (2002). Fat-free mass index and fat mass index percentiles in Caucasians aged 18-98 y. International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity, 26(7), 953-960. link
  • Kyle, U. G., Schutz, Y., Dupertuis, Y. M., & Pichard, C. (2003). Body composition interpretation: contributions of the fat-free mass index and the body fat mass index. Nutrition, 19(7), 597-604. link
  • Kouri, E. M., Pope Jr, H. G., Katz, D. L., & Oliva, P. (1995). Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clinical Journal of Sport Medicine, 5(4), 223-228. link