Cortisol: normal range and what it means
Short answer: The normal cortisol range is 6 – 18.4 µg/dL for adults. In SI units that is about 166 – 508 nmol/L. Labs differ a little, so also check the range printed on your report.
Check your value
Where does your cortisol sit?
Your result
Type the number from your lab report to see where it sits.
Upload your whole lab report and see every marker, with this value already in. Free, no account.
Add the rest of your reportWorked out in your browser. Nothing you type is sent or saved.
Information, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell.
The primary stress hormone — follows a daily rhythm (morning value).
Normal range
Adult reference range.
- Low< 6 µg/dL
- Normal6 – 18.4 µg/dL
- High≥ 18.4 µg/dL
What it measures
Your main stress hormone, highest in the morning. Chronic elevation affects sleep, weight and immunity.
What moves it
Stress, sleep, time of day, caffeine and illness.
How to bring it into range
Sleep, stress management, limiting late caffeine. Test in the morning.
How fast it responds
Varies hour to hour; trends over weeks.
Also reported as: serum cortisol · morning cortisol
See where your own value lands
Upload a lab report and HealthOS reads all 88 markers, personalises every range to your sex and age, and tells you which ones actually need attention. Free, no account needed.
Check my blood testGet this marker explained for your own numbers
We’ll send you a short guide to reading this marker in context — what to check alongside it, and when a value is worth acting on.
One email about this marker. No spam, unsubscribe anytime.
We handle your details as described in our Privacy Policy.
Common questions
- What is the normal cortisol range?
- The normal cortisol range is 6 – 18.4 µg/dL for adults. In SI units that is about 166 – 508 nmol/L. Labs differ a little, so also check the range printed on your report.
- What does a high Cortisol mean?
- A value above the reference band means Cortisol is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my Cortisol?
- Sleep, stress management, limiting late caffeine. Test in the morning.
More in Hormones
Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.