Pediatric safe dose range calculator (mg/kg/day)
Enter your values. The answer and the full worked solution update as you type.
Result
A dose outside the safe range is not given: in exam questions you hold it and contact the prescriber. For exam practice only. This is a study aid, never a clinical decision: always follow the prescription, local protocols and the product information.
Check whether an ordered pediatric dose falls within the safe dose range, the way nursing dosage exams ask it. Enter the child’s weight in kg or lb, the safe range from the drug reference (per day or per dose), the ordered dose and how many doses are given per day. The calculator works out the safe range per day and per dose, the ordered daily dose and whether the order is safe, too low or too high.
Step-by-step solution
Safe range per day
Ordered dose per day
Compare with the safe range
Key formulas
- Daily dose
- mg/day = mg/kg/day × weight (kg)
- Doses per day
- number = 24 h / dosing interval (h)
- Pounds to kilograms
- kg = lb / 2.2
- Units
- 1 mg = 1000 mcg
How to check a pediatric safe dose
- Convert the weight to kg: divide pounds by 2.2, the convention in most dosage calculation exams.
- Multiply the lowest and highest safe doses (mg/kg/day) by the weight to get the safe range in mg/day.
- Work out the ordered daily dose: the ordered dose times the number of doses per day (every 8 hours = 3 doses, every 6 hours = 4, every 12 hours = 2).
- Compare: inside the safe range the order is safe; below it, it is an underdose; above it, an overdose.
- If the range is given per dose (mg/kg/dose), compare the single ordered dose with the range per dose instead.
Questions and answers
What do I do if the dose is not safe?
In exam questions, a dose outside the safe range is not given: you hold the medication and contact the prescriber to clarify the order. An underdose matters too, because it may not treat the condition.
Why divide pounds by 2.2?
Because 1 kg is about 2.2 lb. The exact factor is 2.2046, but dosage calculation courses almost always use 2.2, so this calculator does too.
What is the difference between mg/kg/day and mg/kg/dose?
A range in mg/kg/day is the total for 24 hours, which is then divided over the doses. A range in mg/kg/dose applies to each single dose. Mixing them up is one of the most common errors in pediatric dosing questions.
What if only a maximum dose is given?
Enter 0 as the lowest safe dose. The calculator then only checks that the order does not exceed the maximum.
Should I round the weight first?
Follow your course: many round the weight to one decimal place in kg. This calculator keeps full precision, so a result right on the edge of the range may differ from a heavily rounded hand calculation.
Practise it yourself
Practise Pediatric & critical-care dosing
A calculator gives the answer. In the exam you need the method: practise it with new problems, hints and worked solutions.