In depth
Dosage calculation guides
Free, long-form guides to the method - how to set a calculation up, how the units cancel, how to round, and how to check the result. Every worked example uses hypothetical practice numbers. When you want problems instead of prose, go to practice or the worked examples.
How to set up dimensional analysis so the units cancelSet up dosage calculations as dimensional analysis: chain conversion factors, cancel the units, and audit the setup before you divide anything.8 min readThree ways to set up the same dosage calculationDesired over have, ratio-proportion, and dimensional analysis set up on the same practice problems - and the point where they stop being equivalent.8 min readHow to calculate an IV drip rate in gtt/minWhat a drop factor is, how to calculate a gravity IV drip rate in gtt/min, why time must be in minutes, and how to round to whole drops.8 min readCalculating IV flow rate in mL/hr and infusion timeSet a pump rate from a volume and a time, work backwards to how long a bag will last, and convert decimal hours into hours and minutes.7 min readConverting between metric and household measuresTeaspoons, tablespoons, fluid ounces, and cups converted to millilitres, plus grains to milligrams - the equivalents and how to use them safely.8 min readRounding and decimal places in dosage calculationHow far to round tablets, millilitres, gtt/min, mL/hr, and decimal hours, why you round once at the end, and how to write the result safely.8 min readHow to check a dose against a safe rangeTurn a mg/kg range from a reference into milligrams for one patient, compare the ordered amount, and know what to do when it falls outside.8 min readHow to calculate a weight-based dose in mg/kgConvert pounds to kilograms, tell mg/kg/dose from mg/kg/day, divide a daily dose into equal doses, and check the result against a safe range.9 min read