Enter the total testosterone level and the sex hormone binding globulin level into the calculator to determine the Free Androgen Index. This calculator can also evaluate any of the variables given the others are known.

## Free Androgen Index Formula

The following formula is used to calculate the Free Androgen Index (FAI).

FAI = (TT * 100) / SHBG

Variables:

- FAI is the Free Androgen Index (%)
- TT is the total testosterone level (nmol/L)
- SHBG is the sex hormone binding globulin level (nmol/L)

To calculate the Free Androgen Index, multiply the total testosterone level by 100, then divide the result by the sex hormone binding globulin level. The result is the Free Androgen Index, which is expressed as a percentage.

## What is a Free Androgen Index?

The Free Androgen Index (FAI) is a calculation used to determine the amount of male hormones (androgens) in the bloodstream. It is calculated by dividing the total testosterone level by the sex hormone binding globulin (SHBG) level and then multiplying by 100. This index is often used in diagnosing hormonal disorders, such as polycystic ovary syndrome (PCOS) in women or hypogonadism in men. High levels of FAI can indicate an excess of androgens, while low levels can suggest a deficiency.