Acetaminophen (Tylenol) Dosage by Weight
Calculate weight-based acetaminophen doses for all ages — infants through adults. Includes formulation-specific volumes, tablet counts, hepatotoxicity thresholds, and drug interaction warnings.
Patient Information
Formulation
Recommended Dose
Disclaimer: For educational purposes only. Not a substitute for clinical judgment. Always confirm dosing with a healthcare provider or pharmacist.
Quick Reference Dosing Table
Acetaminophen 10–15 mg/kg (midpoint 12.5 mg/kg shown). The row matching your patient's weight highlights automatically.
| Weight | Dose range (mg) | Liquid 160 mg/5 mL | 325 mg tab | 500 mg tab | Max/day (mg) |
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About This Tool
Tylenol Dose by Weight — All Ages
Acetaminophen (Tylenol, paracetamol) is the world's most widely used analgesic and antipyretic. It is available over-the-counter in dozens of formulations for all age groups, from infant drops to extra-strength caplets. Despite its excellent safety profile at therapeutic doses, acetaminophen is also the leading cause of acute liver failure in the United States, accounting for nearly 50% of all cases. Accurate weight-based dosing is therefore critical for all patients.
Pediatric Dosing: 10–15 mg/kg
For infants, children, and adolescents, acetaminophen is dosed at 10–15 mg/kg per dose, given every 4–6 hours as needed, with a maximum of 5 doses per 24-hour period. The maximum daily dose is 75 mg/kg/day (not to exceed 4000 mg/day in older children and adolescents). Always dose by weight rather than age — children of the same age can have vastly different weights. For infants under 3 months, consult a physician before administering any dose.
Adult Dosing
For adults weighing 60 kg or more, the standard dose is 500–1000 mg every 4–6 hours, with a maximum of 4000 mg per day. For adults under 60 kg, weight-based dosing (10–15 mg/kg/dose) should be used, with a daily cap of 75 mg/kg/day or 4000 mg/day, whichever is lower. Patients with hepatic impairment, chronic alcohol use (≥3 drinks/day), or who are elderly/frail should limit intake to 2000–3000 mg/day.
Hepatotoxicity and Overdose
Acute ingestion of more than 150 mg/kg (or >7.5 g in adults) is potentially hepatotoxic and requires urgent evaluation. The Rumack-Matthew nomogram is used to assess the need for N-acetylcysteine (NAC) treatment based on the serum acetaminophen level 4 hours post-ingestion. Risk factors for hepatotoxicity at lower doses include fasting/malnutrition, chronic alcohol use, and concurrent use of CYP2E1 inducers (e.g., isoniazid, phenobarbital). If overdose is suspected, call Poison Control: 1-800-222-1222.
How Much Tylenol for 150 lbs?
A person weighing 150 lbs (68 kg) can take 500–1000 mg of acetaminophen per dose (1–2 extra-strength 500 mg tablets) every 4–6 hours, up to a maximum of 4000 mg/day. If the patient has liver disease or drinks alcohol regularly, the maximum should be reduced to 2000–3000 mg/day.
🔑 Clinical Pearls
- Check all combination products (cold/flu, sleep aids, opioid combos) for hidden acetaminophen — many patients unknowingly exceed daily limits.
- The FDA recommends a maximum single dose of 650 mg for OTC use and 1000 mg for prescription use.
- IV acetaminophen (Ofirmev) is dosed differently: 15 mg/kg q6h for patients ≥50 kg, with a 4 g/day cap.
- In the elderly, acetaminophen remains first-line for pain but at reduced maximum daily doses (2000 mg/day).
- Acetaminophen has no significant anti-inflammatory activity — it is not an NSAID.
Key References
- U.S. Food and Drug Administration. FDA Drug Safety Communication: Prescription Acetaminophen Products to be Limited to 325 mg Per Dosage Unit. 2011.
- American Academy of Pediatrics. Red Book: 2021 Report of the Committee on Infectious Diseases. 32nd ed.
- Lexicomp. Acetaminophen: Drug Information. UpToDate/Lexicomp, accessed 2024.
- Rumack BH. Acetaminophen hepatotoxicity: the first 35 years. J Toxicol Clin Toxicol. 2002;40(1):3–20.
- Heard K. Acetaminophen (paracetamol) poisoning in adults: Treatment. UpToDate. 2024.
Formula last verified: February 2026