What this calculates
Children vary widely in size, so pediatric medication orders are commonly written as an amount per kilogram, such as 15 mg/kg. The total dose for a particular child is the dose per kg multiplied by the child's weight in kilograms. This page uses the same exact calculation as the Weight-Based Dose Calculator, with pediatric-focused examples.
Formula
Weight (lb) ÷ 2.2 = Weight (kg)
Dose per kg × Weight (kg) = Ordered dose
Pediatric weights are often given in pounds, so convert first. Kilograms are always the smaller number. The calculator keeps the exact weight and rounds only what it displays.
Worked pediatric examples
These are fictional practice numbers, not recommended doses for any medication.
Example 1: weight in pounds
Order: 10 mg/kg. Weight: 44 lb.
44 lb ÷ 2.2 = 20 kg
10 mg/kg × 20 kg = 200 mg
Example 2: an infant in kilograms
Order: 0.5 mg/kg. Weight: 6 kg.
0.5 mg/kg × 6 kg = 3 mg
Example 3: micrograms
Order: 50 mcg/kg. Weight: 33 lb.
33 lb ÷ 2.2 = 15 kg
50 mcg/kg × 15 kg = 750 mcg
Example 4: dose to liquid volume
Calculated dose: 200 mg. Available: 100 mg per 5 mL.
200 mg ÷ 100 mg × 5 mL = 10 mL
The calculator's optional second step runs this Desired ÷ Have × Quantity step for you.
Per-dose vs per-day orders
Some orders give a dose per kg per day to be divided into several doses. Calculate the daily total first, then divide by the number of doses. Example: 30 mg/kg/day for a 20 kg child divided into 3 doses.
30 mg/kg/day × 20 kg = 600 mg/day
600 mg ÷ 3 doses = 200 mg per dose
Common mistakes
- Using the weight in pounds instead of kilograms, which overstates the dose by 2.2 times.
- Multiplying pounds by 2.2 instead of dividing.
- Confusing a per-day order with a per-dose order.
- Mixing up mcg and mg; a 1,000-fold error is easy with small pediatric doses.
- Missing a leading zero: write 0.5 mg, never .5 mg.
What this tool does not do
It does not know any medication, does not suggest a dose per kg, and does not compare your result with a safe range or maximum dose. A result here only means the arithmetic is correct for the numbers you entered.
FAQ
Is this different from the weight-based calculator?
The math is the same. This page focuses on pediatric examples, per-day orders, and common pediatric errors.
Does it check whether a pediatric dose is safe?
No. It only multiplies the values you enter. Checking a dose against a safe range is a clinical step using current references and policy.
Why divide pounds by 2.2?
2.2 lb = 1 kg is the equivalency commonly used in nursing dosage-calculation courses, and this site uses it everywhere.
Sources
Formulas, units, and terminology were checked against these open references. Wording on this page is our own.
- OpenStax, Pharmacology for Nurses — 2.4 Dosage Calculations
- Open RN Nursing Skills (NCBI Bookshelf) — Chapter 5, Math Calculations
- StatPearls (NCBI Bookshelf) — Dose Calculation
All sources · How we build and test calculators
Related tools
- Dosage Calculator — Tablets, capsules, and liquids · D ÷ H × Q
- Weight-Based Dose Calculator — Dose per kg × weight · mg/kg, mcg/kg, g/kg