FFMI (Fat-Free Mass Index) Calculator

This Fat-Free Mass Index (FFMI) Calculator allows you to calculate your fat-free mass index, based on your body fat, weight and height. It also shows your FFMI category.

To estimate your FFMI, complete the following simple steps:

  • 1. Choose the measurement system (imperial or metric)
  • 2. Input your height in either feet and inches or centimetres
  • 3. Enter your weight in lbs or kgs
  • 4. Input your body fat percentage
  • 5. Click the "Calculate" button to generate the results.
FFMI Calculator

Fat-Free Mass Index (FFMI):
Adjusted (Normalized) FFMI:
Fat-Free Mass (FFM):
FFMI Category:

FFMI Formulas

The mathematical formulas to compute the fat-free mass index (FFMI) are listed below:

Fat-Free Mass Index (FFMI): FFMI [kg/m2] = FFM [kg] / (height [m])2
Normalized Fat-Free Mass Index: Normalized FFMI [kg/m2] = FFM [kg] / (height [m])2 + 6.1 × (1.8 − height [m])
Fat-Free Mass (FFM): FFM [kg] = weight [kg] × (1 − (body fat [%] / 100))

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