The Universal Dosing Formula
(Weight in kg × Desired Dose) ÷ Concentration = mL to give
Doctors prescribe medicine in milligrams (How strong), but parents measure liquid in milliliters (how much). This formula bridges that gap.
Example Calculation
A 22 lb (10 kg) baby needs Tylenol at 15 mg/kg.
TARGET DOSE = 10 kg × 15 mg = 150 mg.
Medicine Concentration is 160 mg / 5 mL.
RESULT = 150 ÷ (160/5) = 4.7 mL.
Common Pediatric Dosages (Cheat Sheet)
Acetaminophen (Tylenol)
Dose: 10-15 mg/kg
Freq: Every 4-6 hours
Max: 5 doses/24 hours
Ibuprofen (Advil/Motrin)
Dose: 5-10 mg/kg
Freq: Every 6-8 hours
Age: ONLY 6 months+
Amoxicillin
Dose: 20-40 mg/kg/day
Freq: Divided into 2-3 doses
Note: Finish full course
Frequently Asked Questions
What is the difference between mg and mL?
Mg (Milligrams) is the strength of the drug (how much powder is dissolved). mL (Milliliters) is the volume of liquid you drink. You cannot measure 'mg' directly; you must calculate how many 'mL' contain that dosage based on the concentration listed on the bottle.
Can I use a kitchen teaspoon?
Never. Kitchen spoons vary wildly in size (from 2mL to 7mL). Always use the oral syringe or dosage cup that came with the medication. If you lose it, buy a calibrated oral syringe from the pharmacy. A standard "medical teaspoon" is exactly 5 mL, but your silverware is not.
How do I convert pounds to kilograms for medicine?
Divide the weight in pounds by 2.2. For example, a 22 lb child weighs 10 kg. Most medical dosages are based on the metric system (kg), so this is the first crucial step in any calculation to avoid overdosing.
What if my child vomits the medicine?
If they vomit within 15 minutes of the dose, you can usually give the dose again. If it has been longer than 20 minutes, do not redose, as much of the drug may have already been absorbed. Call your pediatrician for specific guidance.
What is the max dose for Ibuprofen?
The general maximum is 40 mg/kg per day, not exceeding 2,400 mg total (adult max). It should strictly be given every 6 to 8 hours. Never give Ibuprofen to infants under 6 months old unless directed by a doctor, as their kidneys are not mature enough to process it.
Tools & Data Verified by the EverydayCalculators Medical Research Team.
Disclaimer: This calculator is for educational purposes only. Always confirm dosing with your healthcare provider.