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Free & Bioavailable Testosterone Calculator
Estimate free and bioavailable testosterone from total testosterone, SHBG, and albumin using the Vermeulen equation, matched to the ISSAM calculator. Lab interpretation, not a diagnosis.
Free & Bioavailable Testosterone
Default 4.3 g/dL if unsure.
Free testosterone
11.1 ng/dL
2.22% of total · 0.384 nmol/L
Bioavailable testosterone
260 ng/dL
52.0% of total (free plus albumin-bound)
Calculated with the Vermeulen (1999) equation, the same method as the ISSAM free testosterone calculator. Results are estimates that depend on assay accuracy and the fixed binding constants in the model. This is educational lab interpretation, not a diagnosis or a treatment decision. Discuss your results with a clinician.
Frequently asked questions
Educational use only
This calculator is provided for research and educational purposes. Outputs are derived from the values you enter. Always verify your math and consult a licensed physician before acting on any result.