What Is the Pediatric Dosing Calculator?
The Pediatric Dosing Calculator is a free online tool designed for users who need quick, accurate calculations in the practical calculation space. By entering your child's weight, medication, formulation, you get instant results including dose, dose, frequency. No formulas to memorize, no spreadsheets to build — just enter your numbers and get the answer in seconds. Whether you're a beginner or experienced professional, this calculator saves you time and eliminates guesswork.
Why This Calculation Matters
Getting dose right can make the difference between success and costly mistakes. In practical calculation, small errors compound quickly. Manual calculations are error-prone and time-consuming, especially under pressure. This calculator applies proven formulas used by users worldwide, giving you confidence that your numbers are correct. Use it to get accurate results with precision and avoid common pitfalls that trip up beginners.
When Should You Use This Calculator?
This tool is most useful when you know your child's weight and need to find the right dose. It's also great for quick estimates before committing to a decision, and to double-check manual calculations or professional quotes, and when comparing different scenarios side by side. Bookmark this page and come back whenever you need a fast, reliable answer — the calculator is always free and requires no signup.
Pediatric Dosing Calculator
Disclaimer: Always verify with a pharmacist or pediatrician. This tool is for reference only.
Pediatric Dosing Quick Reference — Acetaminophen
Dose at 15 mg/kg using 160 mg/5 mL liquid concentration
| Weight (lbs) | Weight (kg) | Dose (mg) | Dose (mL) | Frequency |
|---|---|---|---|---|
| 12 lbs | 5.4 kg | 80 mg | 2.5 mL | Every 4–6 hr |
| 18 lbs | 8.2 kg | 120 mg | 3.75 mL | Every 4–6 hr |
| 24 lbs | 10.9 kg | 160 mg | 5 mL | Every 4–6 hr |
| 30 lbs | 13.6 kg | 200 mg | 6.25 mL | Every 4–6 hr |
| 36 lbs | 16.3 kg | 240 mg | 7.5 mL | Every 4–6 hr |
| 44 lbs | 20 kg | 300 mg | 9.4 mL | Every 4–6 hr |
| 55 lbs | 25 kg | 375 mg | 11.7 mL | Every 4–6 hr |
| 66 lbs | 30 kg | 450 mg | 14 mL | Every 4–6 hr |
| 77 lbs | 35 kg | 500 mg | 15.6 mL | Every 4–6 hr |
| 88+ lbs | 40+ kg | 500 mg (max) | 15.6 mL | Every 4–6 hr |
How to Use This Calculator
- Enter Your Child's Weight: Type or select your child's weight in the field provided. Use the most accurate value available for best results.
- Enter Your Medication: Type or select your medication in the field provided. Use the most accurate value available for best results.
- Enter Your Formulation: Type or select your formulation in the field provided. Use the most accurate value available for best results.
- Click Calculate: Hit the Calculate button to run the numbers. Results appear instantly below.
- Review Your Results: Check your dose, dose, frequency. Use these figures to inform your next decision or compare against alternative scenarios.
How It Works
Pediatric medication dosing is based on the child's weight to ensure safety and effectiveness. Weight-based dosing accounts for the fact that children metabolize drugs differently than adults.
The basic rule:
- Acetaminophen: 10–15 mg/kg per dose, every 4–6 hours (max 5 doses/day)
- Ibuprofen: 5–10 mg/kg per dose, every 6–8 hours (max 4 doses/day, age 6 months+)
- Diphenhydramine: 1–1.25 mg/kg per dose, every 6–8 hours
- Always use the concentration printed on the package — formulations vary between brands
Never exceed the maximum daily dose regardless of the child's weight. If the calculated dose seems unusually high or low, double-check the child's weight and consult a healthcare provider. Do not give ibuprofen to infants under 6 months.
Tips & Considerations
- Double-check your child's weight before calculating — even small input errors can significantly change your results.
- Run the calculator with different values to compare scenarios and find the optimal approach for your situation.
- Pay attention to both dose and dose — they work together to give you the full picture.
- Bookmark this page for quick access next time you need to get accurate results.
- If you're unsure about your formulation, start with a conservative estimate and adjust from there.
Frequently Asked Questions
How do I dose children's Tylenol by weight?
Acetaminophen (Tylenol) is dosed at 10-15 mg per kg of body weight, given every 4-6 hours as needed, with a maximum of 5 doses in 24 hours. For a 20 kg (44 lb) child, each dose would be 200-300 mg. Always check the concentration on the label.
How do I dose children's ibuprofen by weight?
Ibuprofen (Advil/Motrin) is dosed at 5-10 mg per kg of body weight, given every 6-8 hours as needed. Maximum 4 doses per day. Do not give to infants under 6 months old. For a 20 kg child, each dose would be 100-200 mg.
Should I dose by age or weight?
Always dose by weight when possible — it's more accurate than age-based dosing because children of the same age can vary significantly in weight. Age-based dosing on product labels is a rough guide when you don't know the child's exact weight.
Can I alternate Tylenol and Motrin?
Many pediatricians recommend alternating acetaminophen and ibuprofen every 3-4 hours for persistent fever. For example, give Tylenol, then 3 hours later give Motrin, then 3 hours later give Tylenol again. Always confirm this approach with your pediatrician first.
What is the difference between infant and children's formulations?
Infant drops are typically more concentrated (e.g., 160 mg/5 mL for acetaminophen) so smaller volumes can be given. Children's liquid may be less concentrated. Always check the mg/mL concentration on the package and use the correct measuring device.
What if my child vomits after taking medication?
If the child vomits within 15-20 minutes of the dose, you can generally re-dose. If it has been more than 20-30 minutes, most of the medication has likely been absorbed and you should not re-dose. When in doubt, contact your pediatrician.