When should I use the neonate setting?

For patients 0–28 days old. Neonatal dosing often differs significantly from older infants and children due to immature renal and hepatic function. Always verify against your hospital's neonatal formulary.

What is the maximum dose I should give?

This calculator does not apply drug-specific maximum doses. You must check the maximum against your hospital's paediatric formulary (AMH Children's Dosing Companion in AU, BNF for Children in UK/US).

My patient is 52 kg — use paediatric or adult dosing?

Once a patient reaches or exceeds the adult dose threshold, cap at the adult maximum. Do not exceed the adult dose just because the patient is technically a paediatric patient.

Paediatric Drug Dose Calculator — Free Nurses Calculator

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Transfer from ED arrives — 7-year-old, 22 kg, ordered paracetamol 15 mg/kg. Stock is 120 mg/5 mL. You need the mL to draw up before night handover.

Paediatric Drug Dose Calculator

Paediatric

Age group

Weight (kg)

Imperial mode auto-converts lb→kg

Min dose (mg/kg)

Enter single dose if no range

Max dose (mg/kg) — optional

Leave blank if single dose

Stock concentration (mg/mL)

Route

Total dose (mg) = Weight (kg) × Dose (mg/kg) Volume (mL) = Total dose ÷ Concentration (mg/mL) Example (paracetamol): 20 kg child, 15 mg/kg oral, stock 120 mg/5 mL (24 mg/mL)
Total = 300 mg · Volume = 12.5 mL

💡 Always cross-reference with your hospital's paediatric formulary (e.g. AMH Children's Dosing Companion, BNF for Children) for maximum single dose limits and frequency. An independent second-check is mandatory for all paediatric doses.

Reference: AMH Children's Dosing Companion · BNF for Children (NICE) · ACSQHC Medication Safety

⚕️ Clinical safety: 🇦🇺 Verify with facility drug formulary and senior clinician · Meets AHPRA/ACSQHC standards

1 What this calculator does

Calculates weight-based drug doses for neonates, infants, children and adolescents. Enter the mg/kg order, patient weight, stock concentration and route to get the total dose in mg and the volume to give in mL. Supports dose ranges and auto-converts lb to kg in imperial mode.

2 Formula & professional reasoning

Total dose (mg) = Weight (kg) × Dose (mg/kg) | Volume (mL) = Total dose ÷ Concentration (mg/mL)

Weight-based dosing accounts for the dramatic pharmacokinetic differences between paediatric age groups. Neonates and infants have different distribution volumes, protein binding and hepatic clearance compared to children. The formula is identical to adult weight-based dosing but the safety margins are narrower — small errors have proportionally larger consequences.

3 Worked examples

⚠️ Illustrative example only — not clinical or professional instruction.

Basic

Paracetamol oral — child

Given: 22 kg · 15 mg/kg · stock 120 mg/5 mL (24 mg/mL)

Working: 22 × 15 = 330 mg total · 330 ÷ 24 = 13.75 mL

Answer: 13.75 mL oral

💡 Cross-check: 330 mg is within the paracetamol child max of 15 mg/kg/dose.

Standard

Ibuprofen suspension

Given: 18 kg · 10 mg/kg · stock 100 mg/5 mL (20 mg/mL)

Working: 18 × 10 = 180 mg · 180 ÷ 20 = 9 mL

Answer: 9 mL oral

💡 Illustrative — always verify dose range and frequency with your formulary.

Advanced

Dose range — min to max

Given: 15 kg · 10–15 mg/kg range · stock 50 mg/mL IV

Working: Min: 15×10÷50 = 3 mL · Max: 15×15÷50 = 4.5 mL

Answer: 3–4.5 mL IV

💡 For dose ranges, confirm with prescriber which end of the range is intended.

4 Sanity check

Always verify with formulary

AMH Children's Companion (AU) / BNF for Children (US)

This calculator does not know the maximum safe dose for any specific drug.

Neonate warning

Extra caution — unique pharmacokinetics

Neonatal dosing requires pharmacy or specialist verification for all but the most routine drugs.

Weight accuracy

Always use current weight — not estimated

A 10% weight error = 10% dose error in a weight-based calculation.

Independent double-check

Mandatory for all paediatric doses

Two nurses must independently calculate before any paediatric medication is given.

5 Common errors

Error	Cause	Consequence	Fix
Using estimated weight	Scales not available or omitted	Dose error proportional to weight error	Weigh the patient. Use Broselow tape or APLS formula only in emergencies.
Skipping the independent check	Time pressure or familiarity	Calculation errors go uncaught	Paediatric doses always require two independent calculations before administration
Wrong concentration selected	Multiple stock strengths available	Volume error — potentially 2–10×	Read the concentration from the actual ampoule or bottle in hand
Exceeding adult maximum dose	Child is large (>50 kg) and mg/kg exceeds adult dose	Overdose	Always cap at the adult maximum dose for large children/adolescents