On this page
Copper in two units: the short answer
To convert copper from µg/dL to µmol/L, multiply by 0.157. To go back from µmol/L to µg/dL, multiply by 6.369 (or divide by 0.157). For example, 100 µg/dL × 0.157 = 15.7 µmol/L. The converter above works in both directions and shows where the result sits against typical reference ranges.
What the test measures
Serum copper is reported in µg/dL in the US and µmol/L in SI units. Copper's atomic mass is 63.55 g/mol, so 1 µg/dL = 0.157 µmol/L and 1 µmol/L = 6.36 µg/dL.
Why the units differ
Copper is tested in suspected Wilson disease, copper deficiency (for example after bariatric surgery or with high zinc intake) and in some neurological work-ups.
Where the factor comes from
The conversion factor comes from the molar mass (63.55 g/mol) and the volume units on each side. Laboratories may round the factor slightly differently, which can change the last digit but never the clinical meaning.
How to convert step by step
- Check the unit printed next to the result on your report – µg/dL or µmol/L.
- µg/dL → µmol/L: multiply by 0.157.
- µmol/L → µg/dL: multiply by 6.369.
- Round to the same number of decimals your lab uses.
Worked example in reverse: 9.4 µmol/L × 6.369 = 59.9 µg/dL.
Copper conversion chart
| µg/dL | µmol/L |
|---|---|
| 20 | 3.1 |
| 40 | 6.3 |
| 60 | 9.4 |
| 70 | 11 |
| 80 | 12.6 |
| 100 | 15.7 |
| 120 | 18.8 |
| 140 | 22 |
| 160 | 25.1 |
| 200 | 31.4 |
| µmol/L | µg/dL |
|---|---|
| 3.1 | 19.7 |
| 6.3 | 40.1 |
| 9.4 | 59.9 |
| 11 | 70.1 |
| 12.6 | 80.3 |
| 15.7 | 100 |
| 18.8 | 119.7 |
| 22 | 140.1 |
| 25.1 | 159.9 |
| 31.4 | 200 |
Copper levels: what the numbers mean
| Category | µg/dL | µmol/L |
|---|---|---|
| Low<11 µmol/L | < 70 | < 11 |
| Typical adult rangeAbout 11–22 µmol/L; women and pregnancy higher | 70 – 140 | 11 – 22 |
Typical adult interval. Estrogen, pregnancy and inflammation raise copper because they raise ceruloplasmin.
Typical adult interval. Estrogen, pregnancy and inflammation raise copper because they raise ceruloplasmin.
Interpreting copper results
About 90% of copper in blood is carried by ceruloplasmin, so anything that changes ceruloplasmin changes total copper. Copper deficiency can cause anemia, low white cells and a spinal cord problem that resembles B12 deficiency; it is easy to miss after gastric surgery or with heavy zinc supplement use. Wilson disease is a rare inherited disorder of copper handling and needs specialist testing.
A single result outside the reference range is common and often not significant on its own. Reference ranges are set so that about 1 in 20 healthy people fall outside them, and every laboratory sets its own limits for its method. Use the range printed on your report and discuss results with the clinician who ordered the test.
When to see a doctor
Contact your clinician if a result is flagged as abnormal and you have symptoms, if a value is far outside the range, or if results are changing over time. This page explains units; it cannot diagnose or replace medical advice.
Frequently asked questions
What is 15 µmol/L copper in µg/dL?
15 × 6.36 = 95 µg/dL.
Is serum copper high in Wilson disease?
Usually not – total serum copper is often low because ceruloplasmin is low. Diagnosis relies on ceruloplasmin, urine copper, eye exam and other tests.
Can I use this converter for any lab?
Yes for the unit conversion, which is fixed by chemistry. Reference ranges differ between labs and methods, so compare your converted value with your own lab's range.