Free testosterone calculator
Enter the numbers from your blood test. It works out free and bioavailable testosterone with the Vermeulen equation, the same method most labs use. Enhanced Training Studio keeps every blood test next to your protocol.
A calculation from your numbers, not a diagnosis. Read your result against your own lab's reference range, with your doctor.
Questions
How is free testosterone calculated?
With the Vermeulen equation, the method most labs use when they report a calculated free testosterone. It works out how much testosterone is bound to SHBG and to albumin, and what is left over is free.
What do I need from my blood test?
Total testosterone and SHBG. Albumin helps a little; if your report doesn't have it, the calculator uses 43 g/L, a typical value.
Is calculated free testosterone the same as measured?
Not exactly. The reference method (equilibrium dialysis) is slow and costly, so most labs calculate it the same way as this page. Direct immunoassays for free testosterone are less reliable. Results from different methods aren't directly comparable.
Why doesn't my result match my lab report?
Labs can use slightly different constants or a measured albumin, and they round. Small differences are normal. Your lab's own reference range is the one to read your result against.
What are bioavailable testosterone and the free percentage?
Bioavailable testosterone is the free testosterone plus the part loosely bound to albumin. The free percentage is free testosterone as a share of total testosterone, so you can compare it with your lab report.