The Right Way to Dose Tylenol and Motrin for Kids
If I could tattoo one sentence on every medicine cabinet in America, it would be this: dose by weight, not by age. The box gives age ranges for convenience, but two 4-year-olds can differ by 15 pounds — and that difference is the dose. Here's how to get it right every time.
Key takeaways
- Dose by weight, not age — and recheck the dose as your child grows.
- Read YOUR bottle's concentration: infant drops are much stronger per mL than children's liquid.
- Don't alternate Tylenol and Motrin on your own, and never double-dose medicines that already contain acetaminophen.
- Measure with an oral syringe and write down every dose and time.
The two medicines to know
- Acetaminophen (Tylenol): 10–15 mg per kg of body weight, every 4–6 hours. Max 75 mg/kg/day. Okay for young infants — ask your pediatrician for the dose under 6 months.
- Ibuprofen (Motrin/Advil): 10 mg per kg, every 6–8 hours. Only for babies 6 months and older. Max 40 mg/kg/day.
Full tables by weight are in our medication dosing guide — bookmark it.
The 5 mistakes I see in the ER
- Dosing by age. Weigh your child. Use the weight table. Done.
- Wrong concentration. Infant ibuprofen drops are 3x stronger per mL than children's liquid. The number of mL depends entirely on which bottle you hold — read the label every time.
- Kitchen spoons. A “teaspoon” from your drawer can hold anywhere from 3–7 mL. Use the oral syringe that came with the medicine.
- Double-dosing through cold medicines. Multi-symptom products often already contain acetaminophen. Adding Tylenol on top is an overdose. Read every label.
- Freelance alternating. Alternating Tylenol and Motrin every few hours is a classic error source. Only do it if your pediatrician specifically prescribed the schedule — and write down every dose and time.
Two more rules
Never aspirin for kids (Reye syndrome). And write it down — at 3 AM, “did I already give the Motrin?” is a question you never want to guess at. A phone note takes five seconds.
When in doubt, your pharmacist is a free, underused dosing expert — and your pediatrician's after-hours line exists for exactly these questions.
Frequently asked questions
Should I dose children's medicine by age or weight?
By weight, always. Age-based dosing is an estimate; weight-based dosing is accurate. Use your child's current weight and a weight-based table.
Can babies under 6 months take ibuprofen?
No. Ibuprofen is only for babies 6 months and older. For younger infants, ask your pediatrician about acetaminophen.
Why does the concentration on the bottle matter?
Because the mL you give depends on it — infant drops can be 3x stronger per mL than children's liquid. Always match your dose to your specific bottle's label.
Reviewed by Ali Ozcan, MD, MBA
Board-certified pediatric emergency medicine physician and creator of ER4Kids. This guide reflects the same trusted, evidence-based guidance Dr. Ozcan provides to families in the emergency department.
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