Calculate paediatric doses by weight and body surface area.
Weight-based dosing suits most drugs while surface area dosing is used where clearance tracks metabolic rate, notably in oncology. Clark's rule is a rough scaling and is generally superseded by explicit paediatric dosing. Children are not small adults: organ maturity and body composition change clearance in ways simple scaling cannot capture, which is why paediatric-specific dosing exists.
Pediatric Dose
Mosteller BSA = √(height × weight ÷ 3,600); Clark's rule = weight ÷ 70 × adult dose
This performs arithmetic on figures you supply and does not recommend any drug, dose or route. Medication errors can cause serious harm or death. Always verify every calculation independently, confirm against the prescription and product literature, and follow your institution's double-check procedures. Never self-medicate or alter a prescribed dose. Paediatric dosing carries particular risk because of narrow margins and rapid weight changes. Always use paediatric-specific prescribing references and confirm with a paediatric pharmacist or prescriber.
Mosteller BSA = √(height × weight ÷ 3,600); Clark's rule = weight ÷ 70 × adult dose Weight-based dosing suits most drugs while surface area dosing is used where clearance tracks metabolic rate, notably in oncology. Clark's rule is a rough scaling and is generally superseded by explicit paediatric dosing.
Children are not small adults: organ maturity and body composition change clearance in ways simple scaling cannot capture, which is why paediatric-specific dosing exists.
This calculator takes 5 inputs: Child weight, Child height, Dose per kilogram, Dose per square metre, Adult dose for comparison. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.