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 centimeters
• 3. Enter your weight in lbs or kgs
• 4. Input your body fat percentage
• 5. Click the "Calculate" button to generate the results.

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))

Reference: Kouri E. M., Pope H. G. Jr, Katz D. L., Oliva P. Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clin J Sport Med 1995 Oct; 5(4):223-8.

You may also be interested in our Body Shape Calculator or Weight Loss Percentage Calculator