Child Medication Dose by Weight Calculator
Estimate a generic weight-based pediatric dose in milligrams and millilitres from body weight, dose per kg and liquid concentration.
How it works
Dose (mg) = weight(kg) × dose per kg · Daily = dose × doses per day · Volume (mL) = dose(mg) ÷ concentration(mg/mL) · kg = lb × 0.4536
Most pediatric medicines are dosed by body weight — a set number of milligrams per kilogram — because a child’s size varies far more than an adult’s. This general tool converts the child’s weight to kilograms, multiplies by the per-kg dose you enter, and (given a liquid concentration) works out the millilitres to measure. It deliberately uses whatever mg/kg figure you provide rather than assuming a specific drug, so the exact dose, frequency and maximum must come from the product label or your pediatrician.
Worked example
A 33 lb child is 15.0 kg. At 15 mg/kg the dose is 15 × 15 = 224 mg. With a 32 mg/mL liquid (160 mg per 5 mL), that is 224 ÷ 32 ≈ 7 mL, up to 4 times a day.
Frequently asked questions
Is it safe to dose my child from this alone?
No. This is an educational estimate. Always confirm the correct mg/kg, maximum daily dose and interval from the medicine’s label or your pediatrician or pharmacist before giving any medication — never dose by age or guesswork.
How do I turn “160 mg per 5 mL” into the concentration?
Divide the milligrams by the millilitres: 160 ÷ 5 = 32 mg/mL. Enter that as the concentration and the tool returns the volume to measure per dose.
Why weight instead of age?
Two children of the same age can differ greatly in size, and medicine acts on the body’s mass. Weight-based dosing is more accurate, which is why hospitals use it and product labels list weight bands.
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This is an educational estimate only, not medical advice or a prescription. Always confirm any pediatric dose, maximum and frequency with the product label, a pharmacist or your pediatrician before giving medication.