Children's Tylenol dose calculator

The math the bottle label doesn't show you

Pediatric acetaminophen dosing is 10 to 15 milligrams per kilogram of body weight per dose, given every 4 to 6 hours, with a hard ceiling of 5 doses in 24 hours and 75 mg per kg per day. The middle of the range (12.5 mg/kg) is what most pediatricians reach for. The bottle gives age-banded doses that round down hard at the top end of each band, so a chunky 4-year-old who could safely take a 5-year-old dose gets under-dosed and the fever doesn't budge. Then parents re-dose 30 minutes later, which is the start of the spiral. Weight-based math fixes this. A 30-pound child weighs about 13.6 kg, which means the right dose is 136 to 204 mg per dose. The bottle says 5 mL for ages 2-3, which is 160 mg. Within the safe band, on the lower end. That works for mild fever. For 103°F with chills, 6 mL (192 mg) is still safe and works better. Always confirm with your pediatrician before going to the top of the band.

The daily cap matters more than any single dose. Five doses of the right amount, spaced 4 to 6 hours apart, will not damage the liver. Eight doses (because you forgot when you gave the last one) can.

Why "Infants' Tylenol" and "Children's Tylenol" are the same drug now

Until 2011, Infants' Tylenol was concentrated (80 mg per 0.8 mL) and Children's Tylenol was diluted (160 mg per 5 mL). Parents who had an old bottle of the concentrated version on hand routinely gave Children's-strength doses of Infants' concentrated, which is roughly triple. After hundreds of liver-failure cases, the FDA and manufacturers standardized both to 160 mg per 5 mL. The "Infants'" label now only signals which dosing tool the box ships with: a syringe for small doses, a cup for larger ones. The drug strength is identical.

This matters for two reasons. First, if a relative gives you an old bottle from before 2011, do not use it. Even unexpired, you cannot tell from the label which formula it is. Second, generic store-brand "infants" and "children's" are the same 160 mg per 5 mL. Buy whichever is cheaper. Read every label every time. Some chewables are 80 mg per tablet, some are 160 mg. They look identical.

The five mistakes that cause most overdoses

The FDA tracks accidental acetaminophen poisoning closely because it is the leading cause of acute liver failure in the US. Five patterns show up over and over:

• Dosing by age, not weight. A 25-pound 3-year-old and a 40-pound 3-year-old need different doses. The age band on the bottle assumes the median weight for that age.
• Using a kitchen spoon. A household teaspoon ranges from 3 to 7 mL. The syringe or cup that comes with the bottle is the only accurate tool. If you lose it, the pharmacy gives them out free.
• Doubling up because "it isn't working." Acetaminophen takes 30 to 60 minutes to peak. If the fever hasn't broken at 45 minutes, that's normal. Re-dosing inside 4 hours stacks the drug in the liver.
• Hidden acetaminophen in cold medicine. Most NyQuil, DayQuil, Sudafed PE, Theraflu, and Robitussin combo products contain acetaminophen. Read the active-ingredient list on every box. Never combine without checking.
• Adult Tylenol given by a grandparent. A 325 mg adult tablet is more than double a child's dose. This is the most common scenario in poison-control calls.

Signs of acetaminophen overdose (and what to do)

Acetaminophen overdose has a deceptive timeline. In the first 24 hours after a high dose, symptoms are mild or absent — maybe some nausea or sweating. The liver damage shows up at 24 to 72 hours, by which time treatment options are narrower. Watch for:

• Nausea, vomiting, or loss of appetite within 24 hours of a suspected overdose
• Pain in the upper right side of the belly (where the liver sits)
• Unusual sleepiness or confusion 1 to 3 days after the dose
• Yellow tint in the eyes or skin (jaundice) — late sign, urgent
• Dark urine, very pale stools

If you think you've given too much, call Poison Control immediately at 1-800-222-1222. They will tell you whether the dose was actually toxic for your child's weight or whether you can monitor at home. Most calls end with reassurance — but the cases that don't get caught early are the ones that go badly.

How to use this calculator

Enter your child's weight (toggle pounds or kilograms), pick the age band, and select which Tylenol product you have on hand. The tool returns the recommended dose in milliliters or tablets, the dose in milligrams, the timing (every 4 to 6 hours), and the daily cap. The math is conservative: it uses 12.5 mg/kg as the recommended dose, not the 15 mg/kg ceiling. If your pediatrician told you to use a different dose for your child, follow their guidance over this tool. Write down the time of each dose somewhere visible — a sticky note on the medicine cabinet, the notes app, anywhere you'll see it. Half of accidental over-dosing comes from a tired parent at 2 a.m. who can't remember whether the last dose was at 10 p.m. or midnight.

When to call your pediatrician (and when to call 911)

Call your pediatrician same-day for any fever in a baby under 3 months, fever of 104°F or higher at any age, fever that lasts more than 3 days, or a child who seems unusually drowsy, drinks much less than normal, or has fewer than half their usual wet diapers. Call 911 or go directly to the ER for: stiff neck with fever, a rash that does not blanch when you press a glass on it, difficulty breathing or fast breathing, persistent vomiting and signs of dehydration, lethargy that you cannot rouse them from, a seizure with the fever, or any child under 3 months with a rectal temperature of 100.4°F or higher. Acetaminophen treats the fever, not the cause — if the cause is serious, hiding the fever delays diagnosis. This calculator gives general pediatric dosing guidance based on AAP recommendations. For any concern about your specific child, call your pediatrician or 911 if it is an emergency.