Fried's Rule Calculator
Fried's Rule is a pediatric dosing formula to calculate safe medication doses for infants (under 1 year). Enter the adult dose and infant age in months to estimate the appropriate infant dose.
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
- Educational tool; verify every dose with a clinician and drug reference.
Formula
Infant dose = adult dose × age in months / 150
- Fried's Rule: Infant dose = Adult dose × Age in months ÷ 150
- Maximum age range: 150 months (12.5 years); use adult dose for older children
- Example: 500 mg adult dose, 12-month infant = 500 × 12 ÷ 150 = 40 mg infant dose
- Accuracy: ±10–15% variance based on individual infant metabolism
- Common uses: analgesics, antibiotics, antihistamines
- ⚠ Always verify recommended dose ranges with pharmaceutical literature.
- This calculator provides estimates only. Always consult a healthcare professional before administering medication to infants.
Fried's Rule Example
Inputs
- Adult Dose: 500 mg
- Infant Age: 18 months
Adult dose 500 mg for an 18-month-old infant: 500 × 18 ÷ 150 = 60 mg infant dose (12% of adult dose). Always verify with pediatric dosing guidelines.
Frequently asked questions
What is the Fried's Rule?
The Fried's Rule Calculator is a health and wellness calculator that helps you calculate fried's rule values from your input data. Enter values using the units shown next to each input field (e.g. kg, cm, years).
When should I use this calculator?
Use this calculator whenever you need a quick, accurate result for fried's rule values from your input data without working through the arithmetic manually.
What units should I enter?
Enter values using the units shown next to each input field (e.g. kg, cm, years).
How accurate are the results?
This calculator uses widely accepted health formulas and returns screening estimates only. It does not replace a diagnosis from a qualified healthcare professional.
How do I interpret the result?
Compare your result with published reference ranges. Values outside the normal range warrant a conversation with your doctor.
How can I verify the calculation manually?
Use the displayed formula and work through the numbers step by step. If your manual result differs slightly, check rounding and unit conversions first.
Can I use this for planning and budgeting?
Yes. Run best-case, expected, and worst-case inputs to compare outcomes and make safer planning decisions.
Related calculators
Young's Rule Calculator Young's Rule Calculator is a health and wellness calculator that helps you calculate young's rule values from your input data. The formula used is: Child dose = adult dose × age / (age + 12). Enter values using the units shown next to each input field (e.g. kg, cm, years). Clark's Rule Calculator Clark's Rule Calculator is a health and wellness calculator that helps you calculate clark's rule values from your input data. The formula used is: Child dose = adult dose × (weight in lb / 150). Enter values using the units shown next to each input field (e.g. kg, cm, years). Pediatric Dosage Calculator Pediatric Dosage Calculator is a health and wellness calculator that helps you calculate a pediatric medication dose from body weight and mg/kg per day. The formula used is: Daily dose = weight × mg/kg/day; per dose = daily / doses per day. Enter values using the units shown next to each input field (e.g. kg, cm, years).