FFMI is equivalent to free fat body mass in kilos divided by height in meters squared. The corresponding equation is
fat free mass
It is expressed in kilograms per square meter. The average score for men is 19, and average score for women is about 15.
To perform a proper calculation, we need to know body fat result in percentages. The body fat value estimates what percentage of our total body weight is body fat. The FFMI calculator uses mathematical formulas for computing the fat-free mass, FFMI as well as Normalized FFMI.
For example, let us calculate FFMI for a man who has 1.9 meters, weighs 90 kilograms, and has 24% of body fat. Firstly, we calculate body fat
body fat = 90 ×
= 21.6 kg
The next step is to estimate fat free mass by using its formula, so
fat free mass = 90 × ( 1 −
) = 68.4 kg
Now, the FFMI and normalized FFMI (because the men is taller than the mean value, 1.8m) are given, respectively
normalized FFMI = 18.84 + 6.1 × (1.8 − 1.9) = 18.23
The normalized FFMI is 18.23 kg/m2, it classifies our man to the average result, the message with the classification range is displayed automatically below the calculator.
Fat-Free Mass Index calculator allows us to change the units which are displayed. We can switch between centimeters, meters, kilograms, pounds, etc., according to needs and preferences.