Cortisol Level Calculator

Normal cortisol levels vary significantly by time of day due to the diurnal rhythm. In the morning (6–10 AM), normal serum cortisol is typically 6–23 µg/dL (165–635 nmol/L). Afternoon values are lower, around 3–16 µg/dL, and evening levels drop further to roughly 1–8 µg/dL. Always compare your result to the reference range provided by your specific laboratory.

To convert cortisol from µg/dL to nmol/L, multiply by 27.59. For example, a cortisol level of 18 µg/dL equals 18 × 27.59 = 496.6 nmol/L. This calculator performs all common cortisol unit conversions automatically, including µg/L, ng/mL, and µg/100mL.

The Cortisol:DHEA-S ratio is a marker of adrenal balance and physiological stress. Both hormones are produced by the adrenal glands, but cortisol rises with stress while DHEA-S often declines with age and chronic stress. A high ratio may indicate adrenal imbalance, HPA axis dysregulation, or chronic stress, while a low ratio may suggest suboptimal cortisol production. An optimal Cortisol:DHEA-S ratio (using µg/dL units) is generally considered to be below 5–6.

Elevated cortisol (hypercortisolism) can be caused by Cushing's syndrome, Cushing's disease (a pituitary tumor), prolonged psychological or physical stress, steroid medication use, obesity, depression, or alcoholism. Symptoms may include weight gain around the abdomen, high blood pressure, easy bruising, and fatigue. A healthcare provider should evaluate persistently elevated results.

Low cortisol (hypocortisolism) may indicate Addison's disease (primary adrenal insufficiency), secondary adrenal insufficiency due to pituitary or hypothalamic issues, or adrenal fatigue from chronic stress. Symptoms can include fatigue, weight loss, low blood pressure, salt cravings, and dizziness. Critically low cortisol can be life-threatening and requires urgent medical evaluation.

Yes — cortisol follows a strong circadian (diurnal) pattern. Levels peak shortly after waking (around 6–8 AM) and gradually decline throughout the day, reaching their lowest point around midnight. This is why most cortisol blood tests are performed in the morning for standardization. This calculator adjusts its interpretation based on the sample collection time you select.

DHEA-S (dehydroepiandrosterone sulfate) is an androgenic hormone produced by the adrenal cortex, like cortisol. It serves as a precursor to sex hormones and has anti-aging, immune-supporting, and anti-stress properties. Because cortisol and DHEA-S share the same adrenal pathway, their ratio reflects adrenal function and the body's stress response balance. DHEA-S levels naturally decline with age.

No. This calculator is an educational tool designed to help you understand your lab values and how they compare to reference ranges. It does not constitute a medical diagnosis. Interpretation of cortisol levels requires consideration of symptoms, medications, sample timing, collection method (serum, saliva, or urine), and clinical context. Always consult a qualified healthcare provider for diagnosis and treatment.