Free Androgen Index Calculator

The Free Androgen Index (FAI) Calculator is a valuable tool used in medical and health fields to assess the amount of active testosterone in the body. This index is crucial for diagnosing and managing various hormonal disorders. By providing an easy and precise way to calculate FAI, this tool aids both healthcare professionals and individuals in monitoring their hormone levels.


The Free Androgen Index is important because it helps to determine the balance of active androgens in the body. Androgens, such as testosterone, play a significant role in both male and female health, influencing muscle mass, bone density, and overall well-being. An imbalance in androgen levels can lead to conditions such as polycystic ovary syndrome (PCOS) in women, hypogonadism in men, and other endocrine disorders. Monitoring FAI is essential for diagnosing these conditions, managing symptoms, and guiding treatment plans.

How to Use the Free Androgen Index Calculator

Using the Free Androgen Index Calculator is straightforward:

  1. Enter Total Testosterone Level: Input the total testosterone level in nmol/L.
  2. Enter SHBG Level: Input the Sex Hormone Binding Globulin (SHBG) level in nmol/L.
  3. Click “Calculate”: The calculator will process the inputs and provide the Free Androgen Index value.
  4. View Results: The FAI value is displayed, helping you understand your active testosterone level.

This tool simplifies complex calculations, making it easier to obtain accurate results quickly.

10 FAQs and Answers

1. What is the Free Androgen Index (FAI)?

The Free Androgen Index is a ratio that estimates the amount of free (active) testosterone in the bloodstream. It is calculated using total testosterone and SHBG levels.

2. Why is FAI important?

FAI is crucial for assessing androgen status in the body. It helps diagnose and manage conditions related to hormone imbalances, such as PCOS and hypogonadism.

3. How accurate is the Free Androgen Index Calculator?

The calculator provides precise results based on the input values for total testosterone and SHBG. Accurate input data ensures reliable results.

4. Can both men and women use the FAI calculator?

Yes, the FAI calculator is applicable for both men and women, as it helps in evaluating androgen levels in both genders.

5. What conditions can be diagnosed using the FAI?

Conditions such as PCOS, androgen-secreting tumors, hypogonadism, and other endocrine disorders can be assessed using the FAI.

6. How often should one calculate their FAI?

The frequency of FAI calculation depends on medical advice. Regular monitoring may be necessary for managing hormone-related conditions.

7. What units are used for input in the FAI calculator?

The FAI calculator uses nmol/L for both total testosterone and SHBG levels.

8. Is the FAI calculation a replacement for professional medical advice?

No, the FAI calculation should be used as a supplementary tool. Always consult a healthcare professional for comprehensive diagnosis and treatment.

9. Can lifestyle changes affect FAI?

Yes, factors like diet, exercise, stress, and sleep can influence hormone levels and, consequently, the FAI.

10. Where can I get my testosterone and SHBG levels tested?

Testosterone and SHBG levels can be tested through blood tests ordered by a healthcare provider or at specialized diagnostic laboratories.


The Free Androgen Index Calculator is a vital tool for assessing active testosterone levels in the body, providing insights into hormonal health. By simplifying the calculation process, it aids in the diagnosis and management of various endocrine disorders. Whether you are a healthcare professional or an individual monitoring your hormone levels, the FAI calculator offers a user-friendly and accurate way to understand your androgen status. Regular use, combined with professional medical advice, can help maintain optimal hormonal health and well-being.