Weight-Based Dosing

This formula is used when a medicine dose is prescribed relative to body weight, so larger patients receive proportionally more and smaller patients receive less. You multiply the dose per kilogram by the patient’s weight to convert a standard rate into the total amount needed for that individual. It is especially useful in children, where size varies a lot and fixed doses may not be appropriate.

Use this when a prescription or guideline gives a dose in units like mg/kg, mcg/kg, or mL/kg. It is common in paediatrics, emergency medicine, and for drugs where safety depends on matching the dose to body size.

• Using the patient’s weight in pounds instead of kilograms
• Forgetting to include the units after calculating the dose
• Multiplying by weight when the prescription already gives a fixed total dose