Drugs & toxicology

Phenobarbital unit converter

Barbiturate anticonvulsant level for therapeutic drug monitoring

Also known as: Phenobarbitone, Luminal

Converter

Enter a value in any unit and all other units fill in.

µg/mL µmol/L mmol/L mg/dL µg/dL

Worked example

25 µg/mL (middle of the reference range) = 108 µmol/L

Conversion formulas

µmol/L	µmol/L = µg/mL × 4.306	µg/mL = µmol/L × 0.2322
mmol/L	mmol/L = µg/mL × 0.004306	µg/mL = mmol/L × 232.2
mg/dL	mg/dL = µg/mL × 0.1	µg/mL = mg/dL × 10
µg/dL	µg/dL = µg/mL × 100	µg/mL = µg/dL × 0.01

Reference range

Unit	Adults
µg/mL	10 – 40
µmol/L	43.06 – 172.2
mmol/L	0.0431 – 0.1722
mg/dL	1 – 4
µg/dL	1000 – 4000

Source: Reference ranges for antiepileptic drugs revisited (ILAE ranges), Drug Des Devel Ther 2018 · Last reviewed: 2026-10-14

Note from the source: ILAE 2008 range 10-40 mg/L (43-172 µmol/L); sedation frequent above 30 mg/L

Frequently asked questions

How do I convert Phenobarbital from µg/mL to mg/dL?

mg/dL = µg/mL × 0.1. In the other direction: µg/mL = mg/dL × 10.

What is the reference range of Phenobarbital?

For adults the range is 10 – 40 µg/mL (Reference ranges for antiepileptic drugs revisited (ILAE ranges), Drug Des Devel Ther 2018). Reference ranges differ between laboratories and partly by sex and age; use the range printed on your lab report.

Which units are used for Phenobarbital?

Common units are µg/mL, µmol/L, mmol/L, mg/dL, µg/dL.