Formula

Single dose (mg) = weight (kg) × ordered mg/kg/dose. Total daily dose = single dose × doses per day.

Worked example

Order: 15 mg/kg/dose every 8 hours for a 20 kg child → 20 × 15 = 300 mg per dose; 3 doses/day → 900 mg per day.

Notes

• Convert pounds to kilograms first (1 lb = 0.453592 kg) – the calculator does this for you.
• Orders may be written per dose (mg/kg/dose) or per day (mg/kg/day) – check which one the order uses; this page computes from mg/kg/dose.
• Compare the result against the drug reference maximum – see the Safe Dosage Range Calculator.

Educational use only – for checking and learning medication math. Always verify doses against the order, the drug reference and a pharmacist. Reviewed 2026-08-23.