Testosterone Calculator

For men, a total testosterone reading below 300 ng/dL is treated as below the standard adult reference range, per the AUA (2018) and Endocrine Society (2018) guidelines. That threshold is applied the same way at any adult age -- it does not get lowered for older men. For women, the typical range is much lower, roughly 15-70 ng/dL.

No, and that's a deliberate choice, not an oversight. Average population testosterone does decline gradually with age, but current guidelines specifically warn against lowering the diagnostic threshold to match that trend, because doing so risks writing off genuinely low, treatable testosterone in older men as just 'normal for your age.' This calculator applies one 300 ng/dL floor at any adult age.

Testosterone follows a daily rhythm and peaks in the early morning, so a single afternoon reading can look artificially low even in someone with normal levels. Both the AUA and Endocrine Society guidelines call for a second early-morning measurement to confirm a low result before treatment is considered -- one low number on its own isn't diagnostic.

No. Guidelines require both a confirmed low level (on a second morning test) and symptoms consistent with low testosterone -- fatigue, low libido, reduced muscle mass and similar. Symptoms alone are too non-specific to diagnose on their own, since they overlap with sleep disorders, depression and thyroid disease, and a number alone without symptoms isn't treated as diagnostic either.

Total testosterone only measures the total pool, most of which is bound to sex hormone binding globulin (SHBG) and not biologically active. SHBG itself rises with age, obesity and certain medications, so two people with the same total testosterone can have different amounts of free, active hormone. When a result is borderline, a free or bioavailable testosterone test adds information the total number alone can't provide -- worth discussing with a healthcare provider rather than reading total testosterone in isolation.