Last reviewed: March 2026
This is an educational reference tool only. It does not replace clinical judgment or local guidelines.
Maximum single dose: 1,000 mg. Maximum daily dose: 4,000 mg. Always verify with the treating clinician before administration.
Use specialist guidance for neonates, infants under 3 months, and patients with hepatic impairment.
Acetaminophen (Tylenol) is one of the most widely used medications in children worldwide, making it one of the most common sources of accidental overdose when dosed incorrectly. A reliable calculator removes the guesswork from weight-based dosing and makes the process safer for caregivers and clinicians alike.
Most dosing errors occur because caregivers use age-based guidance printed on packaging rather than weight-based dosing, which can significantly underestimate the correct dose for a small child or overestimate it for a large one. Weight-based dosing is the clinical gold standard.
The calculator handles all common formulations — 120 mg/5 mL, 125 mg/5 mL, and 160 mg/5 mL syrups, as well as concentrated drops and tablets — converting the milligram result directly into the precise volume to draw up, removing a manual conversion step that introduces error.
Enter the child's weight and age, select the preferred formulation, and the calculator returns the single dose in mg, the volume in mL, the maximum daily dose, and the minimum interval between doses.
The default dosing rate of 15 mg/kg per dose is within the recommended clinical range of 10–15 mg/kg, and is adjustable for cases where a prescriber has specified a different rate. The maximum single dose is 1,000 mg and the maximum daily dose is 4,000 mg — both applied automatically as hard caps.
A rounding control allows the volume result to be snapped to the nearest 0.5 mL increment, matching the markings on standard oral syringes and minimising measurement error at the point of administration.
Inline warnings appear automatically when the weight-based calculation approaches or reaches the adult ceiling, when a very young age is entered (under 3 months), or when the mg/kg input falls outside the expected clinical range — helping clinicians catch data-entry errors before they reach the patient.
A session history records each calculation so that dosing for multiple patients, or repeat doses for the same patient at different time points, can be reviewed and exported to CSV for documentation.
The dose calculation uses the child's weight and a weight-based dosing factor, then converts the result to the volume of the chosen formulation.
Syrup 120 mg/5 mL is the older standard concentration found in many parts of the world and is still widely dispensed in community pharmacies. Each 5 mL spoonful contains 120 mg.
Syrup 125 mg/5 mL is common in many countries and is the formulation referenced in several national pediatric formularies. Each 5 mL contains 125 mg.
Syrup 160 mg/5 mL (also labelled as 32 mg/mL) is the formulation adopted for Children's Tylenol in North America after the 2011 reformulation. It provides a more concentrated dose per mL, reducing the volume the child needs to swallow.
Concentrated drops (100 mg/mL) are designed for infants and require careful measurement. They deliver a large dose in a very small volume — the calculator returns the dose in mg only for this formulation, as the exact dropper calibration varies by product.
Tablet 500 mg is appropriate for older children and adolescents who can swallow tablets. Fractions of tablets (half-tablet = 250 mg) are practical for children in the 17–35 kg range.
Acetaminophen is an ingredient in hundreds of over-the-counter combination products — cold remedies, flu syrups, and cough suppressants — making it the leading cause of acute liver failure in children in the developed world, almost entirely from unintentional double-dosing.
Before giving any dose, check the label of every other product the child is currently taking. Products to check include: Calpol, Disprol, Panamax, Panadol, combination cold syrups (e.g., Benylin, DayQuil, NightNurse), and any other analgesic or antipyretic.
The daily ceiling of 4,000 mg (75 mg/kg/day, whichever is lower) applies to the total acetaminophen from all sources combined. If a child is receiving a combination product, subtract that contribution from the available daily allowance before dosing with plain acetaminophen.
Single-dose reference using 15 mg/kg, capped at 1,000 mg. Volume calculated for 125 mg/5 mL syrup. Always round to nearest 0.5 mL for practical measurement.
| Weight (kg) | Dose (mg) | Syrup 120 mg/5 mL (mL) | Syrup 125 mg/5 mL (mL) | Syrup 160 mg/5 mL (mL) |
|---|---|---|---|---|
| 5 kg | 75 mg | 3.1 mL | 3 mL | 2.3 mL |
| 7 kg | 105 mg | 4.4 mL | 4.2 mL | 3.3 mL |
| 10 kg | 150 mg | 6.3 mL | 6 mL | 4.7 mL |
| 12 kg | 180 mg | 7.5 mL | 7.2 mL | 5.6 mL |
| 15 kg | 225 mg | 9.4 mL | 9 mL | 7 mL |
| 18 kg | 270 mg | 11.3 mL | 10.8 mL | 8.4 mL |
| 20 kg | 300 mg | 12.5 mL | 12 mL | 9.4 mL |
| 25 kg | 375 mg | 15.6 mL | 15 mL | 11.7 mL |
| 30 kg | 450 mg | 18.8 mL | 18 mL | 14.1 mL |
| 40 kg | 600 mg | 25 mL | 24 mL | 18.8 mL |
| 60 kg | 900 mg | 37.5 mL | 36 mL | 28.1 mL |
| 67 kg | 1000 mg | 41.7 mL | 40 mL | 31.3 mL |
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Usman Shaoukat is the founder and editor of BestMedCal. He is a computer and web specialist who researches every BestMedCal tool from published standards and medication-safety references, including NIST, the U.S. FDA, NCBI and the American Academy of Pediatrics. His focus is dose-to-volume calculations and unit conversions. Every formula and worked example is checked against the sources listed on each page. BestMedCal has no clinicians on staff: our tools check arithmetic and explain methods; they do not recommend doses. If you spot an error, contact us and we will review it.