DrugTheGuide

Concentration unit converter

Convert between mg/L, mg/dL, mmol/L, mcg/mL, ng/mL, and nmol/L.

Common TDM therapeutic ranges
DrugMW (g/mol)Target range
Lithium 6.94 0.6–1.2 mmol/L
Vancomycin 1449.25 15–20 mg/L (AUC-based)
Digoxin 780.94 0.5–2.0 ng/mL
Phenytoin 252.27 10–20 mg/L
Theophylline 180.16 10–20 mg/L
Gentamicin 477.6 peak 5–10, trough <2 mg/L

Ranges from drug labels on DailyMed. Always verify against current institutional guidelines.

Frequently asked questions

How do I convert mg/L to mmol/L?
Divide mg/L by molar mass (g/mol): mmol/L = mg/L / MW. Example: lithium MW = 6.94 g/mol; 1 mg/L ÷ 6.94 = 0.144 mmol/L. Therapeutic ranges are in drug labels on DailyMed and PubChem.
What is the difference between mg/dL and mg/L?
1 mg/dL = 10 mg/L. US labs report glucose and creatinine in mg/dL; most drug PK studies and European labs use mg/L. Always verify units when comparing to therapeutic ranges. FDA NCA guidance defines PK reporting conventions.
What units are used for therapeutic drug monitoring (TDM)?
Common TDM units: vancomycin trough = mg/L; phenytoin = mg/L or mcg/mL (equivalent — both = μg/mL × 1); digoxin = ng/mL; lithium = mmol/L; gentamicin = mg/L. See each drug's label on DailyMed for reference ranges, and FDA TDM guidance for methodology.
How do I convert ng/mL to nmol/L?
Note: 1 ng/mL = 1 μg/L. To convert to nmol/L: nmol/L = ng/mL × 1000 / MW(g/mol). Find molar masses on PubChem. Example: testosterone MW = 288.4; 5 ng/mL = 5 × 1000 / 288.4 = 17.3 nmol/L.