Pediatric Drug Dosage Calculator (mg/kg)
Calculate single-dose and total daily drug doses for paediatric patients based on weight and mg/kg prescription, with liquid volume per dose.
Results
What is it?
DISCLAIMER: For educational and reference purposes only. All clinical decisions must be made by qualified healthcare professionals. This calculator computes paediatric drug doses based on the mg/kg dosing method, which accounts for the wide variation in drug distribution, metabolism, and elimination across different body weights in children. The result includes single-dose amount in mg, total daily dose, and the volume to administer when using a liquid formulation.
How to use
Enter the child weight in kg, the prescribed dose in mg/kg per dose (from the prescriber order or formulary), the dosing frequency, and the concentration of the liquid preparation. Always verify the prescribed dose against the formulary maximum and the specific indication. Cross-check with a pharmacist before administering.
Example scenario
A 20 kg child prescribed amoxicillin 25 mg/kg/day in 3 divided doses (TID), using 250mg/5mL suspension (50 mg/mL). Single dose = 20 x (25/3) = 166.7 mg. Total daily dose = 20 x 25 = 500 mg. Volume per dose = 166.7 / 50 = 3.33 mL. Round to nearest 0.1 mL using an oral syringe.
Pro tip
Always double-check against published maximum doses — mg/kg calculations can exceed safe limits for larger children. For neonates and premature infants, mg/kg dosing requires additional adjustment factors for organ maturity. Use this calculator as a verification tool alongside a clinical pharmacy system, never as the sole calculation source.