Bilirubin umol/L to mg/dL Converter
Convert total, direct or indirect bilirubin between umol/L and mg/dL using the bilirubin molecular-weight factor, with adult and newborn cautions kept separate from the arithmetic.
Convert Your Bilirubin Result
Converted Bilirubin
21.00 umol/L divided by 17.104 equals 1.23 mg/dL.
Share Or Save
What This Bilirubin Converter Does
This converter changes a bilirubin concentration from micromoles per litre, written here as umol/L, to milligrams per decilitre, written as mg/dL. It also works in the reverse direction. The most common UK search is a laboratory result such as 21 umol/L to mg/dL, because UK hospital and NHS-style reports usually use SI concentration units while many US articles, drug-study tables and older clinical examples use mg/dL.
The page is built for unit copying and record comparison. It does not assess jaundice, liver function, gallstones, Gilbert syndrome, haemolysis, bile duct obstruction or newborn treatment thresholds. Bilirubin may be reported as total bilirubin, direct bilirubin, conjugated bilirubin, indirect bilirubin or unconjugated bilirubin. Those words refer to the fraction measured, not to a different unit factor. A direct bilirubin of 5 umol/L and a total bilirubin of 5 umol/L convert using the same arithmetic, but they are not interpreted in the same clinical way.
Bilirubin Conversion Formula
The factor comes from bilirubin’s molecular weight. PubChem lists bilirubin with molecular weight about 584.7 g/mol. Converting between molar concentration and mass concentration gives a practical clinical factor of about 17.104 umol/L for 1 mg/dL.
mg/dL = umol/L / 17.104
umol/L = mg/dL x 17.104
Many charts round the factor to 17.1. This tool uses 17.104 internally, then rounds the final answer to the number of decimals you choose.
Quick Direct Answer
1 mg/dL bilirubin is about 17.10 umol/L. 1 umol/L bilirubin is about 0.05847 mg/dL. Therefore, 21 umol/L is about 1.23 mg/dL, and 2.0 mg/dL is about 34.21 umol/L.
Total, Direct And Indirect Bilirubin
Lab Tests Online UK describes bilirubin as a yellow pigment formed when red blood cells are broken down. Total bilirubin is commonly reported, and some reports split it into conjugated or direct bilirubin and unconjugated or indirect bilirubin. That split can help clinicians work out whether the pattern points more towards bile flow, liver processing, red-cell breakdown or a benign inherited pattern, but the unit conversion still uses the same bilirubin factor.
If you are comparing two reports, first confirm the same fraction is being compared. A total bilirubin result in umol/L should not be compared with a direct bilirubin result in mg/dL as if they measured the same thing. Convert the unit, then compare total with total, direct with direct, or indirect with indirect. If the fraction labels differ, ask the laboratory or clinician which result is relevant.
Common Bilirubin Conversions
| umol/L | mg/dL | Common Search Or Use |
|---|---|---|
| 5 umol/L | 0.29 mg/dL | Low adult example for checking a portal export. |
| 10 umol/L | 0.58 mg/dL | Typical small-number conversion used in LFT result copying. |
| 17.1 umol/L | 1.00 mg/dL | The rounded clinical bridge between the two unit systems. |
| 21 umol/L | 1.23 mg/dL | Oxford University Hospitals lists 0-21 umol/L for total bilirubin in its catalogue. |
| 34.2 umol/L | 2.00 mg/dL | A reverse check for 2 mg/dL to umol/L searches. |
| 100 umol/L | 5.85 mg/dL | Often seen in jaundice discussions, but the cause cannot be inferred by conversion. |
| 250 umol/L | 14.62 mg/dL | Newborn jaundice pages may use high umol/L numbers that need age-in-hours charts. |
Newborn Bilirubin Needs A Different Check
Newborn bilirubin is one of the easiest places to make a unit mistake. NICE guidance for jaundice in babies under 28 days uses bilirubin in micromol/litre and states that levels are interpreted against the baby’s postnatal age in hours and treatment threshold graphs. A number that looks high on an adult report cannot be judged by adult rules in a newborn, and a number in mg/dL should be converted before it is plotted on a UK-style chart.
This converter does not reproduce phototherapy or exchange transfusion charts. It can change, for example, 14.6 mg/dL to about 250 umol/L, but the next step for a baby is a clinical chart that uses age in hours, gestational age, risk factors, the method of measurement and local hospital policy. If a baby is visibly jaundiced in the first 24 hours, difficult to wake, feeding poorly or worrying the parent or carer, unit conversion is not a substitute for urgent advice from maternity, neonatal or emergency services.
Worked Examples
Enter 21 and choose umol/L to mg/dL. The result is 1.23 mg/dL with two decimal places. The reverse row shows that 1.23 mg/dL maps back close to 21 umol/L after rounding.
Choose mg/dL to umol/L and enter 1.2. The answer is 20.52 umol/L. If copying into a UK report note, round only as much as the form asks.
Select direct or conjugated bilirubin, enter 0.3 and convert to umol/L. The answer is 5.13 umol/L. The fraction label remains important after conversion.
Enter 250 and select the newborn context. The unit result is 14.62 mg/dL, but treatment decisions need the NICE chart or a local neonatal pathway.
How To Avoid Unit And Report Mistakes
- Copy the unit and the bilirubin fraction together, for example “total bilirubin 21 umol/L” rather than just “bilirubin 21”.
- Do not mix direct bilirubin with total bilirubin when comparing two reports.
- Use the report’s own reference interval if you enter a low or high limit; laboratories can use different methods and patient groups.
- For newborns, use age in hours and the local chart after conversion; adult intervals do not apply.
- Ask the requesting clinician about flagged results, symptoms, medication changes, pregnancy, newborn feeding concerns or repeated abnormal values.
Why The Optional Range Is Only A Copy Check
The converter can place the entered value beside a low and high limit you type, but that is not a clinical judgement. MedlinePlus notes that normal results can vary by laboratory, sex and whether the test is being done on an infant or child. Oxford University Hospitals gives a total bilirubin catalogue interval of 0-21 umol/L, while another lab may print a different adult range or a separate direct bilirubin range. The right comparison is the one printed on your own report, alongside any clinician comment.
Reverse Conversion Table
| mg/dL | umol/L | Useful For |
|---|---|---|
| 0.3 mg/dL | 5.13 umol/L | Small direct bilirubin examples. |
| 0.5 mg/dL | 8.55 umol/L | Routine adult LFT comparison. |
| 1.0 mg/dL | 17.10 umol/L | Fast mental check using the rounded factor. |
| 1.5 mg/dL | 25.66 umol/L | Reverse lookup for US-style reports. |
| 2.0 mg/dL | 34.21 umol/L | Common threshold-style search, not a diagnosis. |
| 10.0 mg/dL | 171.04 umol/L | Newborn or jaundice discussions after unit conversion. |
| 15.0 mg/dL | 256.56 umol/L | High newborn-style number that needs age-in-hours guidance. |
FAQ
What is the exact bilirubin conversion factor?
This tool uses 17.104 umol/L per 1 mg/dL, based on bilirubin molecular weight around 584.7 g/mol. Many clinical tables round this to 17.1.
Is umol/L the same as micromol/L?
Yes. The letter u is used here as an ASCII way to write micro. A UK report may show micromol/L, umol/L or the Greek micro symbol before mol/L.
Does the factor differ for direct bilirubin?
No. Total, direct, conjugated, indirect and unconjugated bilirubin use the same unit factor. The clinical meaning changes with the fraction, not the arithmetic.
Can this page say whether bilirubin is high?
No. It can compare with a range you type, but it cannot judge cause, severity, urgency or treatment. Use the report comment and medical advice.
Why do newborn bilirubin values look much higher?
Newborn jaundice is judged with age-in-hours and gestation-based charts. UK neonatal guidance commonly uses umol/L, so mg/dL values often need conversion before plotting.
Should I round before or after converting?
Convert first, then round the final display. Rounding the input early can move the answer, especially when converting small direct bilirubin values.
Sources
- MedlinePlus. (n.d.). Bilirubin Blood Test. U.S. National Library of Medicine. https://medlineplus.gov/lab-tests/bilirubin-blood-test/
- Lab Tests Online UK. (n.d.). Bilirubin. Lab Tests Online UK. https://labtestsonline.org.uk/tests/bilirubin
- Oxford University Hospitals NHS Foundation Trust. (n.d.). Bilirubin. Oxford University Hospitals. https://www.ouh.nhs.uk/biochemistry/tests/tests-catalogue/bilirubin.aspx
- NICE. (n.d.). Jaundice In Newborn Babies Under 28 Days. National Institute for Health and Care Excellence. https://www.nice.org.uk/guidance/cg98
- National Center for Biotechnology Information. (2025). PubChem Compound Summary For CID 5280352, Bilirubin. PubChem. https://pubchem.ncbi.nlm.nih.gov/compound/Bilirubin