Fat Free Mass Index (FFMI) Calculator

Units:

Description

The **Fat Free Mass Index (FFMI)** is a measurement that adjusts the lean body mass (fat-free mass) for height, providing a more accurate assessment of muscle mass compared to BMI. It's useful for bodybuilders, athletes, and individuals interested in tracking muscle development.

How to Use

Select the unit system: "Imperial" for pounds and inches, or "Metric" for kilograms and centimeters.
Enter your weight and height in the chosen unit system.
Enter your body fat percentage.
Click the "Calculate FFMI" button to see the calculated Fat Free Mass Index.
The result will be displayed below the button, showing your FFMI and categorizing it.

How to Calculate FFMI Manually

To manually calculate FFMI, use the following steps:

Calculate Fat-Free Mass (FFM) using the formula:
FFM = Weight × (1 - (Body Fat Percentage / 100))
Convert height to meters (if using imperial units, divide height in inches by 39.37).
Calculate FFMI using the formula:
FFMI = FFM / Height² (in meters)
For bodybuilders, adjust FFMI by adding 6.1 if height is below average:
Adjusted FFMI = FFMI + (6.1 × (1.8 - Height))
Example: If weight is 180 lbs, height is 70 inches, and body fat is 15%:
FFM = 180 × (1 - 0.15) = 153 lbs
Height in meters = 70 / 39.37 = 1.778 m
FFMI = 153 / (1.778²) ≈ 24.17