Core formulas, worked examples, and practice problems with answers, medication math made manageable.
Always double-check calculations and follow your facility's independent double-check policy for high-alert medications.
Order: amoxicillin 500 mg PO. Available: suspension 250 mg per 5 mL.
D ÷ H × Q → 500 ÷ 250 × 5 mL = 10 mL
Order: acetaminophen 650 mg PO. Available: 325 mg tablets. How many tablets?
Answer: 2 tablets. 650 ÷ 325 × 1 = 2.
Order: digoxin 0.125 mg PO daily. Available: 0.25 mg scored tablets. How many tablets?
Answer: 0.5 tablet. 0.125 ÷ 0.25 × 1 = 0.5. Only split tablets that are scored and approved for splitting.
Order: cephalexin 750 mg PO. Available: suspension 250 mg per 5 mL. How many mL?
Answer: 15 mL. 750 ÷ 250 × 5 = 15.
Order: 1,000 mL normal saline IV over 8 hours. What rate do you set the pump (mL/hr)?
Answer: 125 mL/hr. 1000 ÷ 8 = 125.
Order: 1,000 mL over 8 hours by gravity. Tubing drop factor: 15 gtt/mL. What is the drip rate?
Answer: 31 gtt/min. (1000 × 15) ÷ 480 min = 31.25 → round to 31.
Order: 10 mg/kg PO for a child weighing 22 lb. How many mg per dose?
Answer: 100 mg. 22 ÷ 2.2 = 10 kg; 10 × 10 = 100 mg.
Our full medication math package is part of the digital resource library.
Educational content only
This material is published by Wahero Health Institute for professional education and is not individual medical advice, a care protocol, or a substitute for clinical judgment. Always follow your facility's policies, your state's nurse practice act, and your own scope of practice, and confirm medication doses against a current authoritative reference before administration. See our Terms of Use.