What this result means
Select the bilirubin label and unit printed on the laboratory report, enter one value, and convert that same labelled concentration to the selected equivalent unit. One mg/dL equals 17.104 µmol/L and exactly 10 mg/L. [1][2]
What the three bilirubin units mean
Why bilirubin uses 17.104
The AMA unit converter gives 17.104 µmol/L for 1 mg/dL of total or direct serum bilirubin. An FDA review independently derives the commonly rounded 17.1 factor from a bilirubin molecular weight of 584.66 and the mass and volume prefixes. [1][2]
The factor is specific to bilirubin. It must not be reused for glucose, creatinine, cholesterol or another biomarker because different substances have different molecular weights. [2]
Keep total, direct and indirect labels separate
The same unit arithmetic can express a total, direct (conjugated) or indirect (unconjugated) bilirubin concentration in another supported unit, but those labels describe different reported quantities. Select the source label before calculating so the accessible result carries it forward; this tool does not combine or infer fractions. [1][3]
Choose mg/dL, mg/L or µmol/L exactly as printed
How the result is rounded
The calculator represents every factor as bounded integers over integers, including exact reverse division by 17.104 and 1.7104, and converts direct unit pairs without a rounded intermediate. It rounds once to two decimals for display. Those decimals explain the calculation but cannot add precision that the source laboratory did not report. [1][2]
What the conversion cannot tell you
The converted number does not classify the result or identify a cause. Reference intervals differ by test type, laboratory, assay, age and clinical context; interpretation must use the original report rather than the converted number alone. [3]
This calculator is not a neonatal jaundice or treatment tool. Newborn decisions can depend on age in hours, gestational age, risk factors and the measurement method, none of which this conversion collects.
Safe next steps
Keep the original test label, value, unit, laboratory reference interval, assay notes and test date beside the converted number. Use the result only to compare the same bilirubin fraction in equivalent units. For interpretation, symptoms or a care decision, use the complete original report and qualified professional advice.
Formula and assumptions
- Formula
- µmol/L = mg/dL × 17.104; mg/dL = µmol/L ÷ 17.104. mg/L = mg/dL × 10; mg/dL = mg/L ÷ 10. µmol/L = mg/L × 1.7104; mg/L = µmol/L ÷ 1.7104. [1][2][3]
- Version
- Serum or plasma bilirubin mass-to-amount unit conversion, ama-fda-bilirubin-clinical-unit-conversion-v1
- Rounding
- Use exact integer numerator and denominator factors, then round once to two decimals. Exact halfway ties round upward in magnitude; a positive value below display resolution uses a less-than result.
Who this is for — and when not to use it
Intended use
Neutral, reversible unit conversion for a person who already has one serum or plasma total, direct (conjugated) or indirect (unconjugated) bilirubin result in mg/dL, µmol/L or mg/L, selects that source label and needs the equivalent reporting unit.
Not intended for
This tool does not interpret bilirubin, diagnose a liver, blood or bile-duct condition, apply a reference interval or neonatal treatment threshold, combine bilirubin fractions, assess symptoms or choose or adjust treatment.
Exclusions
- Bilirubin interpretation, health bands, reference intervals and treatment thresholds
- Diagnosis or probability of liver, blood, gallbladder, bile-duct or another condition
- Neonatal jaundice assessment, age-in-hours charts, phototherapy or exchange-transfusion decisions
- Combining, subtracting or changing total, direct (conjugated) and indirect (unconjugated) bilirubin fractions
- Urine, bile, transcutaneous readings or any specimen other than an existing serum or plasma laboratory result
- Medication, treatment and urgent-care decisions
- Any analyte other than bilirubin
- Changing, correcting or reconstructing precision absent from the source laboratory result
Evidence sources
- 1. Units of measure converter: direct and total serum bilirubin — AMA Manual of Style. Accessed Aug 11, 2026.
- 2. FDA clinical review explaining the bilirubin conversion factor — U.S. Food and Drug Administration, Center for Drug Evaluation and Research. Accessed Aug 11, 2026.
- 3. Atellica CH Total Bilirubin 2 assay instructions for use — Siemens Healthineers. Accessed Aug 11, 2026.