Paracetamol Dosage Calculator

Calculate a weight-based paracetamol (acetaminophen) dose per administration, the liquid volume for a given suspension strength, and the maximum doses and total mg allowed in 24 hours.

Quick Facts

Standard dose rate
10-15 mg/kg per dose
Given every 4-6 hours, per widely published pediatric and adult dosing guidance.
Daily ceiling
Lower of 75 mg/kg/day or 4000 mg
The 4000 mg absolute cap applies once weight-based dosing would otherwise exceed it.

Your Results

Calculated
Dose per administration
-
Weight x dose rate, capped at 1000 mg
Volume per dose
-
Based on liquid concentration
Max doses per 24 hours
-
Limited by interval and daily cap
Max daily dose
-
75 mg/kg/day, capped at 4000 mg

Ready

Enter body weight and dosing details, then calculate.

About the paracetamol dosage formula

Paracetamol (acetaminophen) dosing is normally expressed as a rate per kilogram of body weight, given at a fixed interval, with an upper limit on how much can be taken in 24 hours. This calculator applies that standard weight-based formula: it multiplies body weight by a dose rate of 10 to 15 mg/kg, applies a 1000 mg single-dose ceiling, and caps the daily total at the lower of 75 mg/kg/day or 4000 mg. It is a computational tool only and does not replace product labeling, a pharmacist, or a clinician.

How the calculation works

The dose per administration is body weight in kilograms multiplied by the chosen dose rate (10 to 15 mg/kg), rounded down to a maximum of 1000 mg per dose regardless of weight - that single-dose ceiling reflects standard adult dosing limits. The maximum number of doses in 24 hours is the smaller of two limits: how many times the chosen dosing interval (every 4, 6, or 8 hours) fits into a day, and how many doses of that size fit under the maximum daily amount. The maximum daily amount itself is the lower of 75 mg per kilogram per day or an absolute 4000 mg per day, since larger patients would otherwise be calculated to exceed the standard adult ceiling. When a liquid concentration is supplied, the calculator divides the mg dose by that concentration (in mg per mL) to show the corresponding volume for a suspension or drops formulation.

Interpreting the results

  • The dose per administration and volume per dose describe a single dose only - multiply by the number of doses to see the running daily total.
  • If the dose is shown as capped at 1000 mg, weight times dose rate exceeded the standard single-dose ceiling; the calculator is not suggesting a higher amount is unsafe to avoid, only that 1000 mg is the conventional upper bound per administration.
  • Liquid concentrations vary by product and country (common suspensions include 120 mg/5 mL and 250 mg/5 mL). Always confirm the concentration printed on the specific bottle before converting a dose to a volume.

Important disclaimer

This tool performs standard dosing arithmetic for educational and informational use. It does not constitute medical advice and should not be used to determine dosing for infants, during pregnancy or breastfeeding, for anyone with liver or kidney disease, or for anyone taking other paracetamol-containing products. Confirm dosing with a pharmacist, physician, or the product label before administering any medication.

Frequently Asked Questions

What formula does this paracetamol dosage calculator use?
It multiplies body weight in kilograms by a dose rate of 10 to 15 mg per kilogram to get the dose for a single administration. That dose is capped at 1000 mg per administration. The maximum amount in 24 hours is the lower of 75 mg per kilogram per day or 4000 mg, and the maximum number of doses per day is limited by both the dosing interval and that daily cap.
How is the liquid volume per dose worked out?
Divide the calculated dose in milligrams by the concentration of the liquid paracetamol suspension in milligrams per milliliter. For example, a 300 mg dose from a 24 mg per mL suspension (equivalent to 120 mg per 5 mL) works out to 12.5 mL. Always check the concentration printed on the specific product label, since suspensions are sold in several different strengths.
Why is there a maximum daily dose limit?
Paracetamol is metabolized by the liver, and total daily intake above the standard ceiling is associated with a higher risk of liver injury. The two limits used here, 75 mg per kilogram per day for weight-based dosing and an absolute 4000 mg per day for larger individuals, reflect widely published dosing guidance. This calculator performs the arithmetic only; a pharmacist or clinician should confirm dosing for a specific person, especially for infants, pregnant patients, or anyone with liver disease.

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