Pharmacy tools
Pediatric Dose Calculator
Estimate pediatric doses with Clark's rule, Young's rule, or mg/kg weight-based dosing.
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Version 1.0.0 · Last reviewed
Tool
Result
Live output from your inputs
Enter values and calculate to see results.
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Introduction
Estimate a pediatric dose with Clark's rule, Young's rule, or direct mg/kg. These classic rules are teaching aids — labeled pediatric dosing and clinical judgment always take priority.
Disclaimer: This tool is for informational purposes only and is not professional medical, pharmaceutical, financial, or tax advice. Always verify doses with a licensed clinician or pharmacist.
Formula
Clark's rule scales the adult dose by weight in pounds over 150. Young's rule scales by age over age plus 12. Prefer labeled mg/kg when available.
- Dc — Estimated child dose
- Da — Adult dose
- w_lb — Child weight in pounds
- a — Child age in years
Step-by-step
- Choose Clark's, Young's, or mg/kg.
- Enter the adult dose (for Clark/Young) or mg/kg amount.
- Enter child weight and/or age as required by the method.
Worked example
A 20 kg (~44 lb) child with a 500 mg adult dose by Clark's rule: 500 × (44/150) ≈ 147 mg.
Use cases
- Practice classic pediatric dose rules
- Roughly estimate a weight- or age-scaled dose
- Compare mg/kg against Clark/Young estimates
Frequently asked questions
Which method should I use?
Use the product label or pediatric reference when available. Clark's and Young's are historical approximations, not modern standards of care.
Why convert to pounds for Clark's?
Clark's rule is defined with weight in pounds and a 150 lb adult reference. The tool converts kg → lb for you.
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