Pediatric Dose Calculator

How to Use This Calculator

1. Enter the child's weight in kg.
2. Enter the recommended dose per kg from the prescriber or drug reference.
3. Enter the maximum single dose — the calculator caps automatically.
4. Use the Common Drugs tab for built-in dosing for acetaminophen, ibuprofen, amoxicillin, azithromycin, and cetirizine.
5. Use the Professional tab to calculate liquid volume, BSA, and renal adjustment notes.

Formula

Example

Frequently Asked Questions

• How do you calculate a pediatric dose? ▼
  The standard formula is: Dose (mg) = Weight (kg) × Dose per kg (mg/kg). Always apply a maximum single dose cap. For example, acetaminophen at 15 mg/kg for a 20 kg child = 300 mg — well within the 1,000 mg max single dose. Never exceed adult maximum doses regardless of weight.
• What is the most common pediatric dosing error? ▼
  The most dangerous error is a 10-fold (10×) dose error — caused by a decimal point mistake. This calculator includes a 10× error check output to help flag these situations.
• What is BSA-based dosing and when is it used? ▼
  Body Surface Area (BSA) dosing using mg/m² is used primarily for chemotherapy and some critical care drugs where weight-based dosing is less accurate. BSA is calculated using the Mosteller formula: BSA (m²) = √(weight kg × height cm / 3600).
• How do I calculate liquid volume for a pediatric dose? ▼
  Volume (mL) = Dose (mg) ÷ Concentration (mg/mL). For example, acetaminophen oral suspension 160 mg/5 mL = 32 mg/mL. A 300 mg dose ÷ 32 mg/mL = 9.4 mL.
• How does renal impairment affect pediatric dosing? ▼
  Many drugs require dose reduction or interval extension in children with renal impairment. Mild impairment (GFR 30-60) typically requires 25-50% dose reduction. Always consult drug labeling or a clinical pharmacist for renally-cleared drugs.

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