Fat Free Mass Index Calculator

FFMI is an alternative to BMI where in FFMI, the muscle along with fat mass is considered based on height and weight. But the muscle mass is not taken into consideration in BMI. This online Fat Free Mass Index Calculator calculator will help you to find your FFMI using your body fat.

Calculate Fat-Free Mass Index

Unit system

MetricEnglish

Weight

kg

lbs

Body Fat

%

Height

cm

feet

inches

Lean

kg

lbs

Fat Free Mass Index (FFMI)

Adjusted FFMI

Fat Free Mass Index Formula

Lean = Weight * ( 1.0 – (BodyFat / 100.0 ))
FFMI = ( Lean / 2.2 ) / ((Height * 12.0 + Inches) * 0.0254)²
Adjusted FFMI = FFMI + ( 6.0 * ( ((Height * 12.0 + Inches) * 0.0254) – 1.8 ))

Fat free mass index is useful for athlete people who has muscle rich body.

Example

A person weighing 50 kgs, with body 12 % and height 5’4 will have

Lean Weight =

=50 * (1.0 – (12 / 100))
= 50 * ( 1 – 0.12)
= 50 * 0.88
= 44.00 kg

FFMI

= ( 44 / 2.2) / ((5*12.0) + 4)*0.0254)^2
= 20 / ((60 + 4) * 0.0254)^2
= 20 / (1.6256)^2
= 20 / 2.6425
= 7.56

Adjusted FFMI

= FFMI + (6* 5 + 12.0 + 4) * 0.0254) – 1.8
= 7.56 + ( 6.0 * ( ((5 * 12.0 + 4) * 0.0254) – 1.8 ))
= 6.522

Fat Free Mass Index Normal Range

The following table introduces the FFMI scores and their interpretation in terms of muscle mass:

FFMI score	Muscle mass interpretation
16 – 17	Below average
18 – 19	Average
20 – 21	Above average
22	Excellent
23 -25	Superior
26 – 27	Suspicion of steroid use*
28 – 30	Steroid usage likely**