Quick answer. The right dose of acetaminophen (Tylenol) or ibuprofen (Motrin, Advil) for a child depends on weight, not age. Find your child’s weight in the charts below and use the matching dose in milliliters, measured with the syringe that came with the bottle. Children’s acetaminophen (160 mg per 5 mL) can be repeated every 4 to 6 hours, no more than 5 doses in 24 hours. Children’s ibuprofen (100 mg per 5 mL) can be repeated every 6 to 8 hours, no more than 4 doses in 24 hours, and is only for babies 6 months and older. If your baby is under 3 months old and has a fever, please call us before giving any medicine at all.
Fever medicine is for comfort. A fever by itself is not dangerous, and a child who is drinking, resting, and reasonably content does not need medicine just to bring a number down. When your child is miserable, though, the right dose helps, and the wrong dose is one of the most common medication mistakes we see. This page exists so you never have to guess from the side of the box.
Five rules before you reach for the bottle
- Any fever under 3 months: call us first, before any medicine. A rectal temperature of 100.4°F (38.0°C) or higher in a baby under 3 months is a reason to call us, day or night. The acetaminophen chart below starts at 3 months for exactly that reason, and the ibuprofen chart starts at 6 months, so a fever before then is a call, not a dose. Fever at this age can be the first sign of something serious, and medicine can hide it. In the first month of life, that call is more urgent still, and we may send you straight to the emergency department.
- No ibuprofen under 6 months. It has not been shown to be safe in younger babies, and it is not approved for them. Acetaminophen is the only option before 6 months, and only after 3 months unless we have told you otherwise.
- Never both “just to be safe.” Alternating acetaminophen and ibuprofen is not something we recommend on your own, because it is the setup for most of the double-dosing calls we get. If we suggest alternating for a specific illness, we will give you a written schedule.
- Use the syringe, never a kitchen spoon. A kitchen teaspoon can hold anywhere from 3 to 7 mL. The syringe in the box is the only measuring tool that gives the number on this chart. If you lost it, any pharmacy will hand you one.
- Check every label for hidden acetaminophen. It hides inside many cold, flu, and “nighttime” products, and this is the one that trips up careful parents. Read every label, and do not give a combination product to a child under 6 years at all.
Acetaminophen (Tylenol) dosing by weight
Use the children’s liquid, 160 mg per 5 mL. Since 2011, infant and children’s acetaminophen in the United States has been made in this one strength, so the “infant” and “children’s” bottles hold the same medicine and the dose is the same for the same weight. Give every 4 to 6 hours as needed, and no more than 5 doses in 24 hours.
| Child’s weight (3 months and older, unless we tell you otherwise) | Liquid 160 mg/5 mL | Dose in mg | Chewable 160 mg tablets (4 years and older) |
|---|---|---|---|
| 6 to 11 lb | 1.25 mL | 40 mg | Not for this weight |
| 12 to 17 lb | 2.5 mL | 80 mg | Not for this weight |
| 18 to 23 lb | 3.75 mL | 120 mg | Not for this weight |
| 24 to 35 lb | 5 mL | 160 mg | 1 tablet |
| 36 to 47 lb | 7.5 mL | 240 mg | 1 and 1/2 tablets |
| 48 to 59 lb | 10 mL | 320 mg | 2 tablets |
| 60 to 71 lb | 12.5 mL | 400 mg | 2 and 1/2 tablets |
| 72 to 95 lb | 15 mL | 480 mg | 3 tablets |
| 96 lb and up | 20 mL | 640 mg | 4 tablets |
Chewable tablets are for children 4 years and older. Below that age, use the liquid. A chewable is a choking risk in a younger child, and the liquid doses more precisely anyway.
A few notes on the acetaminophen chart. The 6 to 11 lb row is there for babies past 3 months who are still small, and for the rare case where we have told you to dose a younger baby. A fever after 2-month vaccines is the usual example. The label on the bottle, and the AAP, both say to check with a doctor before giving acetaminophen to a child under 2. This chart is that guidance from us. If your child is under 2 and you have not dosed from this chart before, or the weight you are using is more than a couple of months old, call us and we will confirm the row before you give the first dose.
Watch the product strength too. Do not give 500 mg extra-strength products to a child under 12, and do not give 650 mg extended-release products to anyone under 18. Rectal suppositories come in different strengths and are dosed the same as the liquid for the same weight, but ask us before using one.
Ibuprofen (Motrin, Advil) dosing by weight
Use the children’s liquid, 100 mg per 5 mL, for babies 6 months and older. Give every 6 to 8 hours as needed, and no more than 4 doses in 24 hours. Ibuprofen sits easier on the stomach with a feeding or a snack, and we would rather you skip it when a child is vomiting, not drinking, or dehydrated, because it is harder on the kidneys in that state. Use acetaminophen instead until the fluids are back.
| Child’s weight (6 months and older) | Liquid 100 mg/5 mL | Dose in mg | Chewable 100 mg tablets (6 years and older) |
|---|---|---|---|
| 12 to 17 lb | 2.5 mL | 50 mg | Not for this weight |
| 18 to 23 lb | 3.75 mL | 75 mg | Not for this weight |
| 24 to 35 lb | 5 mL | 100 mg | 1 tablet |
| 36 to 47 lb | 7.5 mL | 150 mg | 1 and 1/2 tablets |
| 48 to 59 lb | 10 mL | 200 mg | 2 tablets |
| 60 to 71 lb | 12.5 mL | 250 mg | 2 and 1/2 tablets |
| 72 to 95 lb | 15 mL | 300 mg | 3 tablets |
| 96 lb and up | 20 mL | 400 mg | 4 tablets |
Chewable tablets are for children 6 years and older. Below that age, use the liquid. A chewable is a choking risk in a younger child, and the liquid doses more precisely anyway.
Watch the ibuprofen concentration. Unlike acetaminophen, ibuprofen still comes in two strengths. The infant drops are 50 mg per 1.25 mL, which is twice as concentrated as the children’s liquid, so a dose from the infant bottle is half the number of milliliters on this chart. If you have the drops, use only the syringe that came with them and dose by the milligrams in the Dose in mg column, not by the mL. The drops are made for babies and toddlers. Once your child has outgrown that bottle, switch to the children’s liquid rather than drawing up several syringes of drops, which is its own way to make a mistake. When in doubt, call and read us the label.
Why weight, and not age
Two healthy 2-year-olds can weigh 22 pounds and 34 pounds. The box lumps them into one age band, and one of them gets a dose that is either too small to help or larger than it needs to be. Weight is what the body actually uses to handle the medicine, so weight is what we dose on.
For parents who like to see the math, acetaminophen is dosed at roughly 10 to 15 mg per kilogram per dose, and ibuprofen at roughly 5 to 10 mg per kilogram per dose. A 20 lb baby weighs about 9 kg, so the acetaminophen range works out to about 90 to 135 mg, and the chart row for 18 to 23 lb gives 120 mg, which is 3.75 mL of the 160 mg per 5 mL liquid. Read the pounds and use the row your child’s weight lands in. If the weight falls between two rows, or below the first row on either chart, call us rather than guessing. If you do not know the current weight, use the last one from a visit or a bathroom scale, and use age from the box only as a last resort.
What to do if you gave too much
It happens, usually because two caregivers each gave a dose or a spoon stood in for a syringe. Call Poison Control at 1-800-222-1222 right away. It is free and open 24 hours a day, and they will tell you whether your child needs to be seen. Then call us. Do not wait for symptoms, because an acetaminophen overdose can cause no symptoms at all for the first day and still injure the liver.
When to call us
Fever medicine is for comfort, so the medicine itself is rarely the emergency. The illness underneath sometimes is. Call us if your child:
- Is under 3 months old and has a rectal temperature of 100.4°F (38.0°C) or higher, day or night, and before you give any medicine. In the first month of life, that call cannot wait until morning
- Has a fever that lasts more than 2 to 3 days, or a fever that comes back after going away for a day
- Is not drinking, has far fewer wet diapers than usual, or cannot keep fluids down
- Is hard to wake, unusually limp, or not making eye contact with you
- Has trouble breathing, a stiff neck, a rash that does not fade when pressed, or a seizure
- Still looks miserable an hour after a correct dose, or seems sicker each time the medicine wears off
- Got a double dose, an extra-strength adult product, or a dose from a spoon, even if they seem fine
- Just does not seem right to you
Weight-based dosing is the reason we tell every family to ask us for the right amount on our baby fever, teething fever, and swimmer’s ear pages. These charts start at 3 months for acetaminophen and 6 months for ibuprofen. If anything about them does not fit your child, a medication they already take, a kidney or liver condition, or a weight that seems off, call us before you dose.
What we hear on the nurse line
The call we get most often on this subject starts the same way. A parent measured out “one teaspoon” with a spoon from the drawer, then measured a second dose with the syringe a few hours later, noticed the syringe held a lot less, and realized the first dose had been closer to double. Our nurses walk them through it, and in most of these calls the child is fine, but every one of them was avoidable with the syringe in the box.
Frequently asked questions
How much Tylenol can I give a 20 lb baby?
What is the Tylenol dose per kg for a child?
Can I alternate Tylenol and Motrin?
Should I dose by age or by weight?
Reviewed by Mike Jordan, MD, FAAP. Last reviewed September 8, 2026. Doses follow the American Academy of Pediatrics and Schmitt Pediatric Telephone Protocols weight-based tables for United States products, with maximum daily doses based on weight.
Mike Jordan, MD, FAAP is a Board Certified pediatrician at East Lake Pediatrics, an NCQA-recognized Patient-Centered Medical Home.
East Lake Pediatrics is dedicated to promoting best practices, supporting consistency in our care, and helping ensure the best possible outcomes for the children we serve. To that end, we offer a range of educational resources, both online and as printed handouts, as part of our mission to serve our community. This material is provided for general educational purposes only. It does not constitute medical advice and is not a substitute for professional diagnosis, treatment, or the individualized guidance of your child’s physician. Always talk with your pediatrician or another qualified provider about questions regarding your child’s health, and never disregard or delay seeking care because of something you have read here. If you believe your child is experiencing a medical emergency, call 911 or go to the nearest emergency department.
