Infant Tylenol Dosage Calculator

Infants' Tylenol is acetaminophen liquid with 160 mg in every 5 mL, given with the oral syringe in the box¹. The amount is not worked out from a formula. It is read from a chart that groups children by weight, or by age when the weight is not known.

What the Infant Tylenol Dosage Calculator Measures

It finds the chart row for your child and shows the mL, the mg in that amount, how often it can be repeated and the most doses allowed in 24 hours. It does not judge whether your child needs medicine, and it does not replace the label, your child's doctor or a pharmacist.

The Formula

Dose (mL) = the amount in the chart row for your child's weight (age only if weight is unknown)

Dose (mg) = dose (mL) x 32, because 160 mg / 5 mL = 32 mg per mL

Most in 24 hours = 5 doses, given no closer than every 4 hours

The label says, "If possible, use weight to dose; otherwise, use age"¹.

How This Calculator Computes Your Result

Confirm your bottle says 160 mg per 5 mL, then enter weight (lb or kg) and age in completed months. Kilograms are converted to pounds and part pounds are rounded down, so a borderline weight stays in the lower row. If weight and age point to different rows, the result follows weight; if they are far apart, it asks you to check the lb or kg setting. No amount is shown under 3 months, at 48 months or older, under 6 lb or over 35 lb.

What Your Result Means

The Drug Facts label lists only one dose: 5 mL for 24 to 35 lb, ages 2 to 3. For children under 24 lb or under 2 years it says "ask a doctor"¹. The lower rows below come from the weight chart pediatricians use², and the AAP says acetaminophen should not be given under age 2 without a doctor's guidance³. So for those rows, the result tells you to check the amount with your child's doctor.

The weight rows and amounts are from the Schmitt dose table², and the usual ages are from a state health department chart that lists the same amounts⁴. The label says to repeat the dose every 4 hours while symptoms last, no more than 5 times in 24 hours, and warns that more than 5 doses in 24 hours may cause severe liver damage¹. Above 35 lb the Infants' label lists no dose; Children's products are covered on our Tylenol Dosage Calculator.

How to Give It

The label steps for the enclosed syringe are: shake well, push the air out of the syringe, put the tip into the bottle opening, flip the bottle upside down, pull to the right mark, then give the liquid slowly into the child's mouth, toward the inner cheek¹. Use only the syringe that came in the box¹. The AAP says never to use teaspoons, tablespoons or other household spoons, because they come in many sizes⁵. FDA also warns not to mix and match dosing devices between products⁶.

Do not give Infants' Tylenol with any other medicine that contains acetaminophen, prescription or not¹. Acetaminophen is in many cold, flu and pain products, so read every label. The label lists warfarin and liver disease as reasons to ask a doctor or pharmacist first¹.

If your child gets too much, call Poison Control at 1-800-222-1222 right away, even if your child seems fine¹. The line is free and confidential⁷.

When to Call the Doctor About a Fever

A fever is 100.4°F (38.0°C) or higher taken in the bottom, ear or forehead, or 100°F (37.8°C) by mouth⁸. These are the AAP's points for when to call⁸:

The NHS uses similar cut-offs: get urgent advice for a baby under 3 months at 38C or higher, or 3 to 6 months at 39C or higher⁹. The label adds: stop and ask a doctor if fever gets worse or lasts more than 3 days, or pain lasts more than 5 days¹.

Why There Is Only One Infants' Strength

Infants' acetaminophen used to come as concentrated drops of 80 mg per 0.8 mL or 80 mg per mL⁶. Different strengths for infants and children caused dosing confusion and errors, so an FDA advisory committee asked for one strength, and in 2011 makers began a voluntary switch to 160 mg per 5 mL⁶. FDA's 2015 guidance says children's liquid acetaminophen should have 160 mg per 5 mL, with directions in mL only¹⁰. The old drops were 2.5 to about 3 times as strong, so this chart must never be used with an old bottle.