Dose unit converter
Convert between mg, mcg, mmol, mEq, and mg/kg.
Common drug molar masses
Ibuprofen 206.28 g/mol
Paracetamol 151.16 g/mol
Aspirin 180.16 g/mol
Metformin 129.16 g/mol
Atorvastatin 558.64 g/mol
Amoxicillin 365.4 g/mol
Omeprazole 345.42 g/mol
Losartan 422.91 g/mol
Amlodipine 408.88 g/mol
Metoprolol 267.36 g/mol
Full molar masses on PubChem.
Frequently asked questions
How do I convert mg to mmol?
Divide mg by molar mass (g/mol): mmol = mg / MW. Example: ibuprofen MW = 206.28 g/mol; 400 mg ÷ 206.28 = 1.94 mmol. Molar masses are available on PubChem for every compound.
What is mEq and when is it used?
Milliequivalent (mEq) measures chemical charge equivalents. For monovalent ions (Na⁺, K⁺): 1 mmol = 1 mEq. For divalent ions (Ca²⁺, Mg²⁺): 1 mmol = 2 mEq. Used extensively in IV electrolyte calculations. See NCBI PK overview and DailyMed electrolyte labels.
How is mg/kg dose converted to a total dose?
Total dose = mg/kg × weight (kg). For paediatrics or obesity, choose the correct weight: actual, ideal (IBW), or adjusted (AdjBW). See the BMI & body weight calculator for IBW/AdjBW. FDA guidance on weight-based paediatric dosing is at FDA paediatric drug development.