Bilirubin Units Converter
Convert a serum bilirubin result between mg/dL and µmol/L instantly, and see how your value compares with typical adult reference ranges for total and direct bilirubin.
Convert Your Bilirubin Result Between mg/dL and µmol/L
Bilirubin Units Formula
Where:
- mg/dL — milligrams per deciliter, the unit used in the United States
- µmol/L — micromoles per liter, the unit used in most of Europe and elsewhere
- 17.1 — the conversion factor, derived from the molecular weight of bilirubin (584.66 g/mol)
The factor 17.1 comes from unit chemistry: 1 mg/dL equals 0.01 g per liter, and dividing by the molar mass gives 0.01 / 584.66 × 10⁶ ≈ 17.1 µmol/L. The same factor works in both directions, so one multiplication or division converts any bilirubin value between the two unit systems.
Bilirubin Units – Calculation Example
Example: a lab report from a European hospital shows a total serum bilirubin of 14 µmol/L, but your doctor's chart uses mg/dL. You enter 14 as the concentration, select µmol/L as the unit and Total bilirubin as the context.
\[ 14 \div 17.1 = 0.82 \text{ mg/dL} \]
Result: 14 µmol/L ≈ 0.82 mg/dL — within the typical adult reference range for total bilirubin (about 0.2–1.2 mg/dL, or 3.4–20.5 µmol/L).
How to Use the Bilirubin Units Converter
- Enter your bilirubin value from the lab report in the Bilirubin concentration field (e.g. 0.8).
- Choose the unit printed on your report — mg/dL or µmol/L — in the Unit dropdown next to the value.
- Select the Context: either Total bilirubin or Direct (conjugated) bilirubin. This does not change the conversion; it only decides which reference range is used for the interpretation.
- Read the results: the converter shows your value in both mg/dL and µmol/L, plus a short interpretation of what the value means.
What Is Bilirubin and Why Two Units Exist
Bilirubin is a yellow compound produced when the body breaks down old red blood cells. The spleen releases bilirubin into the blood, the liver converts it into a water-soluble (conjugated, or "direct") form, and it is then excreted in bile. Because this process touches the blood, the liver and the bile ducts, bilirubin is one of the most informative markers on a standard liver panel: elevated levels cause jaundice (yellowing of the skin and eyes) and point to where the problem may lie.
Lab reports express bilirubin in one of two unit systems. The United States uses mass-based units, milligrams per deciliter (mg/dL), while most other countries use molar units, micromoles per liter (µmol/L). Both describe exactly the same concentration — they just scale it differently. A total bilirubin of 1.0 mg/dL is the same as 17.1 µmol/L. This is why the same result can look "high" on one report and "normal" on another if you read the units carelessly.
The calculator also gives a rough interpretation. Typical adult ranges are about 0.2–1.2 mg/dL (3.4–20.5 µmol/L) for total bilirubin and 0.0–0.3 mg/dL (0–5.1 µmol/L) for direct bilirubin. Mildly elevated total bilirubin is very common and often harmless — Gilbert syndrome, a genetic variant affecting roughly 3–8% of people, routinely pushes total bilirubin slightly above the range without any liver damage. Values above roughly 3 mg/dL (about 51 µmol/L) usually deserve medical workup, and very high values suggest significant liver or biliary disease.
Keep in mind that the ratio between direct and total bilirubin matters as much as the absolute number. A predominantly direct (conjugated) elevation suggests a liver or bile-duct problem, while a mainly indirect elevation points to increased red blood cell breakdown (hemolysis) or Gilbert syndrome. Your clinician reads the two values together with other liver enzymes.
Assumptions, Limitations and Practical Tips
- One factor fits all fractions. Total, direct and indirect bilirubin all use the same conversion factor of 17.1 because the factor depends only on the molecular weight of bilirubin, not on which fraction is measured.
- Reference ranges vary. Each laboratory sets its own range, and values differ with age. In newborns, bilirubin normally rises in the first days of life and is assessed with age-specific nomograms, not adult ranges — this tool does not evaluate newborn jaundice.
- Interpretation is not diagnosis. The "What this means" text is a general guide. Bilirubin must be interpreted by a clinician alongside other tests such as ALT, AST, ALP and albumin, and in the context of medications, fasting and symptoms.
- Check the unit before comparing. The most common mistake is comparing a µmol/L value against an mg/dL range (or vice versa), which makes a normal result look seventeen times too high. Always confirm the unit printed on the report.
- Rounding. The calculator displays mg/dL to two decimals and µmol/L rounded to the nearest whole number, matching how most lab reports present these values.
If you work with other lab values reported in mixed units, you may also find our cholesterol units converter, the HbA1c converter, the vitamin D units converter and the testosterone units converter useful for the same reason — translating between mass-based and molar reporting units.
Frequently Asked Questions
How can I convert bilirubin by hand without a calculator?
Multiply mg/dL by 17.1 to get µmol/L, or divide µmol/L by 17.1 to get mg/dL. For a quick mental estimate, you can round the factor to 17: \( 0.8 \text{ mg/dL} \times 17 \approx 14 \text{ µmol/L} \). For the reverse direction, dividing by 20 gives a rough lower-bound estimate, but use the exact 17.1 whenever precision matters, such as comparing a result with a reference range.
Why do my two lab reports show very different numbers for the same test?
Almost certainly the units differ. A US report in mg/dL and a European report in µmol/L will show numbers about seventeen times apart for the same concentration — for example, 0.8 mg/dL and 14 µmol/L are identical results. Before assuming anything changed, check the unit printed next to the value and convert both reports to the same unit. The difference is arithmetic, not medical.
How do I calculate indirect (unconjugated) bilirubin?
Indirect bilirubin is not usually measured directly — labs report total and direct (conjugated) bilirubin, and indirect is the difference: \( \text{indirect} = \text{total} - \text{direct} \). Subtract in the same unit. For example, if total is 1.2 mg/dL and direct is 0.3 mg/dL, indirect is 0.9 mg/dL. The same 17.1 factor converts any of the three fractions between mg/dL and µmol/L.
At what bilirubin level does jaundice become visible?
Yellowing of the eyes (scleral icterus) usually becomes noticeable when total bilirubin exceeds about 2–3 mg/dL, roughly 35–50 µmol/L, depending on skin tone, lighting and the person. Below that, even mildly elevated bilirubin typically causes no visible signs. If you notice yellowing of your skin or eyes, contact a clinician — visible jaundice generally warrants an evaluation of liver function and bile ducts.
What is a normal bilirubin level and what counts as high?
Typical adult ranges are about 0.2–1.2 mg/dL (3.4–20.5 µmol/L) for total bilirubin and 0.0–0.3 mg/dL (0–5.1 µmol/L) for direct bilirubin, but each laboratory sets its own limits. Values slightly above the range are common and often harmless, while levels above roughly 3 mg/dL (about 51 µmol/L) usually deserve medical workup. Reference ranges also differ for children and newborns, so have a clinician interpret your specific result.
Can fasting, diet or exercise change my bilirubin result?
Yes. Prolonged fasting can raise total bilirubin, noticeably so in people with Gilbert syndrome, a harmless genetic variant affecting 3–8% of the population. Strenuous exercise and dehydration can also nudge values upward, while certain medications alter bilirubin metabolism. If a mildly elevated result surprises you, ask your doctor whether a repeat test under normal eating and activity conditions makes sense before drawing conclusions.