Reference arithmetic only
This tool multiplies a stated mg/kg dose by body weight and compares the result with a maximum single dose entered by the user. It does not choose a medicine, dose rate, interval, formulation, or cap. Those values must already be verified from the exact label or a clinician or pharmacist. The output is a numerical cross-check, never a medical recommendation.
Worked example with a cap
A verified instruction of 10 mg/kg for a 24 kg child produces 24 × 10 = 240 mg. If the verified maximum is 300 mg, 240 mg remains below it. At 35 kg, the multiplication gives 350 mg, so the result must be limited to the entered 300 mg cap. The arithmetic cannot decide whether either instruction is suitable.
Milligrams are not millilitres
The result is active-ingredient milligrams. A liquid volume needs the exact concentration, such as 160 mg per 5 mL; a tablet count needs its exact strength and whether splitting is permitted. Never read 240 mg as 240 mL. Brand names can contain different strengths or several active ingredients, creating a duplicate-dose risk that this single calculation cannot find.
Facts that can make a dose unsafe
Age, allergy, kidney or liver disease, dehydration, pregnancy, other medicines, prior doses, and current symptoms can change what is safe. Labels may use age bands instead of mg/kg or prohibit use below a threshold. Do not use this calculation to override a package insert, prescription label, poison-centre instruction, or pharmacist advice.
When to seek help instead
Ask a pharmacist or clinician when product, concentration, interval, maximum, or eligibility is uncertain. Seek urgent help or poison-control guidance for a suspected overdose, severe allergic reaction, trouble breathing, unconsciousness, seizure, persistent vomiting, or unsupervised ingestion by a child. Do not wait for arithmetic or induce vomiting unless qualified guidance says to.
Different from nutrition estimates
Calorie, protein, and water pages are planning estimates with adjustable assumptions. This page is deliberately narrower: it checks multiplication against independently authorised inputs. It does not calculate daily totals, treatment duration, interactions, concentrations, or an appropriate medicine.
Safe checking sequence
Read the active ingredient, strength, route, and maximum from the exact package. Confirm current kilograms, the verified mg/kg instruction, and the time of the last dose. Apply the stated cap, then have another adult or pharmacist check any conversion to mL or tablets. Record the time and amount actually given so another caregiver does not repeat it. This browser calculation stores nothing on the site.