Free Testosterone Index

Quick rough estimate using your lab results for total testosterone and SHBG. Uses a simple Free Androgen Index (FAI) calculation.

Input units: nmol/L Uses total T & SHBG For information only

What this calculator does:

Lets you plug in your total testosterone (nmol/L).
Uses your lab’s SHBG (nmol/L).
Returns a single number: Free Androgen Index (FAI).

This is a rough index only. It does not replace clinical free-testosterone calculations or lab reports. Always discuss lab results with a qualified clinician – do not change any medication, dose, or therapy based on this tool.

Enter your lab values

Total Testosterone nmol/L

SHBG nmol/L

Free Androgen Index (FAI)

dimensionless

Enter values above and tap “Calculate” to see an estimated index.

For proper reference ranges or full free-testosterone calculations, use your lab report and talk to your clinician. Back to TRT dosage tools →