Infant Fever Dosage Calculator
Enter weight accurately — dosing is based entirely on body weight.
Age enables ibuprofen age-block (under 6 months) and acetaminophen under-3-month emergency alerts.
Enter body temperature to assess fever severity and get age-specific guidance.
Enter Your Child's Weight
Enter your child's weight and select a medication to see the recommended dose range, safety alerts, and dosing instructions.
How to Use This Calculator
Enter Your Child's Weight
Weigh your child accurately on a scale if possible. Enter the weight and toggle between lbs and kg. Dosing accuracy depends on having the correct weight — do not estimate if avoidable.
Enter Age and Select Medication
Optionally enter your child's age in months or years to activate critical safety alerts (ibuprofen is blocked under 6 months; acetaminophen triggers an emergency alert for infants under 3 months with fever). Then choose acetaminophen or ibuprofen.
Choose the Formulation
Select the specific formulation you have at home. The concentration (mg/mL) varies between products and determines the volume in mL. Check your product label and match it to the formulation shown.
Read the Dose Range and Safety Alerts
The calculator shows a minimum-to-maximum dose range in mL and mg, dosing frequency, daily maximum, and fever severity if a temperature was entered. Review all safety banners carefully before administering any medication.
Frequently Asked Questions
Why does this calculator show a dose range instead of a single number?
The dose range reflects the clinically accepted window recommended by the American Academy of Pediatrics: 10–15 mg/kg for acetaminophen and 5–10 mg/kg for ibuprofen. The lower end is a safe, effective starting dose for mild symptoms. The upper end provides maximum therapeutic effect for more severe pain or high fevers. Giving a dose anywhere within this range is considered safe. Most caregivers can use a dose in the middle of the range. Never exceed the upper end of the range or the absolute daily maximum.
Can I give acetaminophen and ibuprofen at the same time?
No — do not give both medications at the same time. However, some pediatricians recommend alternating them: give acetaminophen first, then give ibuprofen 3–4 hours later, then repeat the cycle. This approach can help maintain more consistent fever control for persistent high fevers. Because each medication has its own daily maximum limit, you must track doses of each separately and never exceed those limits. Alternating should only be done under the guidance of your child's pediatrician, as keeping track of two medications simultaneously increases the risk of dosing errors.
My baby is 5 months old. Why is ibuprofen blocked?
Ibuprofen is not approved by the FDA for use in infants younger than 6 months of age. This restriction exists because very young infants' kidneys are not mature enough to safely process ibuprofen, creating a risk of kidney damage. Additionally, research on ibuprofen safety and efficacy has not been conducted in infants under 6 months. For infants in the 0–5 month range with fever or discomfort, acetaminophen (with age-appropriate caution) is the only recommended over-the-counter option — always consult your pediatrician before giving any medication to an infant this young.
What is the difference between Infants' Tylenol and Children's Tylenol?
As of 2011, the FDA standardized acetaminophen products so that Infants' Tylenol Oral Suspension and Children's Tylenol Oral Suspension now share the same concentration: 160 mg per 5 mL (32 mg/mL). This change was made specifically to reduce the risk of accidental overdose from confusing two products with different concentrations. Previously, infants' drops were more concentrated (80 mg/mL). Always verify the concentration on your specific product label — some older products may still be in home medicine cabinets, and product formulations outside the US may differ.
When should I NOT treat a fever with medication?
The American Academy of Pediatrics advises that the purpose of treating fever is to improve your child's comfort, not to normalize the temperature number. Fever itself is a healthy immune response. If your child has a mild fever (100.4–102°F) but is alert, playful, drinking fluids, and not appearing distressed, medication may not be necessary. You should always treat fever in infants under 3 months of age as a medical emergency and seek care — do not give medication and wait. In older children, focus on the child's behavior and comfort level rather than the thermometer reading.
What should I do if I think I gave too much medication?
If you believe you may have given your child too much acetaminophen or ibuprofen, act immediately — do not wait for symptoms to appear. Call Poison Control at 1-800-222-1222 (United States) right away. They are available 24 hours a day, 7 days a week and can advise you on whether emergency care is needed. Early treatment of acetaminophen overdose is critical — liver damage may not be apparent for 24–72 hours, and the antidote is most effective when given early. Signs of overdose include nausea, vomiting, extreme sleepiness, and abdominal pain, but symptoms may initially be absent.