# Calculating your FMI

The fat mass index allows you to evaluate the proportion of fat in the body

### Definition of FMI

Are you wondering **what is the fat mass index**? Would you like to know **how** **to find out your fat mass index**? It’s actually very easy, because the calculation is based on your weight, height, age and your gender.

Here’s the formula used to calculate your FMI:

- FMI in % = (1.2 x your BMI) + (0.23 x your age) - (10.8 x your gender
*(female = 0, male =1)*) - 5.4

The FMI shows the proportion of fat in your body.

#### The ideal fat mass index

The ideal fat mass index for women is between 25 and 30%.

- FMI lower than 25%: the person is too thin
- FMI between 25% and 30% inclusive: the person is normal
- FMI above 30%: the person has too much fat

The ideal fat mass index for men is between 15 and 20%

- FMI lower than 15%: the person is too thin
- FMI between 15% and 20% inclusive: the person is normal
- FMI above 20%: the person has too much fat