FFMI Calculator (Fat-Free Mass Index)
Lean mass, fat mass and FFMI with a muscularity rating · free, no signup
See FFMI Calculator (Fat-Free Mass Index) in action
FFMI Calculator (Fat-Free Mass Index)
Enter your weight, height and body fat percentage to get your lean mass, fat mass, FFMI and height-adjusted (normalized) FFMI with a rating from below average to superior.
Useful to see how muscular you are relative to height, independent of fat.
Key features
Lean and fat mass
kg.
FFMI and normalized FFMI
Height adjusted.
Rating
For men and women.
How to use it
- Enter weight, height and body fat %.
- Read your FFMI and rating.
Worked example
Example
80 kg, 178 cm, 15% body fat: lean mass 68 kg, FFMI 21.5, normalized 21.6 (above average).
Who uses this tool
Lifters
Track muscle gain.
Fitness enthusiasts
Understand body composition.
Tips for the best results
- Use a reliable body fat estimate.
Common mistakes to avoid
- Treating FFMI as a diagnosis.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
What is a natural limit?
Most natural lifters top out around 22 to 25 FFMI (men).
Is it free and private?
Yes. It is free with no signup. Everything runs in your browser and anything saved stays on your own device.