Cortisol nmol/L to µg/dL Converter
Instantly convert blood cortisol levels from nanomoles per litre (nmol/L) to micrograms per decilitre (µg/dL). Accurate for interpreting medical and laboratory test results.
Calculate Your Cortisol Conversion
Enter your blood cortisol level in nanomoles per litre (nmol/L) below to get an instant, accurate conversion to micrograms per decilitre (µg/dL).
Cortisol Unit Converter
Enter your lab result to see the equivalent metric value
Enter the value exactly as it appears on your laboratory report
Converted Cortisol Level
Calculated based on cortisol molar mass (362.46 g/mol)
Typical Cortisol Reference Ranges
Standard reference ranges for blood cortisol levels throughout the day. Use this to contextualise your converted results. (Note: Always refer to your specific lab's reference range, as methodologies vary).
| Time of Day | nmol/L (SI Unit) | µg/dL (Traditional) | Context |
|---|---|---|---|
| Morning (8:00 AM) | 138 – 690 | 5.0 – 25.0 | Peak daily cortisol level |
| Afternoon (4:00 PM) | 69 – 414 | 2.5 – 15.0 | Mid-day decline |
| Midnight (12:00 AM) | < 138 | < 5.0 | Nadir (lowest point) |
| 24-Hour Urine Free | 55 – 276 | 15 – 75 µg/24h | Different unit (µg/24h), included for context |
Cortisol Conversion FAQ
Everything you need to know about converting cortisol units for your medical or laboratory results.
To convert cortisol from nanomoles per litre (nmol/L) to micrograms per decilitre (µg/dL), divide the nmol/L value by 27.59. Alternatively, you can multiply the nmol/L value by 0.03625. The formula is: µg/dL = nmol/L ÷ 27.59.
Normal cortisol levels vary depending on the time of day due to the body's circadian rhythm. Typically, morning (8 AM) levels are 138–690 nmol/L (5.0–25.0 µg/dL), afternoon (4 PM) levels are 69–414 nmol/L (2.5–15.0 µg/dL), and midnight levels should be below 138 nmol/L (< 5.0 µg/dL). Always consult your doctor for interpretation.
nmol/L is the standard SI (Système International) unit used in the UK, Canada, Australia, and most of Europe. µg/dL is the traditional unit still predominantly used in the United States. Both measure the exact same thing, just on different numerical scales.
Yes. The conversion factor between molar units (nmol/L) and mass units (µg/dL) depends entirely on the molecular weight of the specific substance. This calculator is specifically calibrated for cortisol (hydrocortisone), which has a molar mass of approximately 362.46 g/mol.