Dosage calculations are a core nursing skill for safe medication administration and NCLEX success. This free practice quiz includes 25 dosage calculation questions with answers and rationales to help you review the most common nursing math problems you’ll see in school and on exams. You’ll practice tablet and liquid doses, mg/kg pediatric dosing, IV flow rates in mL/hr and gtt/min, insulin and heparin calculations, and weight‑based infusions.
Work each problem on paper first, then click “Show Answer & Rationale” to check your math and understand the steps. As you go, focus on the key formulas (Desired ÷ Have × Volume, mg/kg, and rate = volume ÷ time) and double‑check units and rounding. When you’re ready for more practice, use the links at the end of this quiz to explore additional pharmacology, dosage calculations, and NCLEX practice questions on NurseStudy.net.
NCLEX RN Dosage Calculation Questions (With Hidden Answers and Rationales)
Practice these NCLEX-style dosage calculation questions. Click on “Show Answer and Rationale” to reveal the correct answer and explanation.
1. Ampicillin IM Dose
Question: The order is for ampicillin 500 mg IM every 6 hours. The vial reads 250 mg/mL. How many mL will you administer per dose?
Show Answer and Rationale
Answer: 2 mL
Rationale: Divide the ordered dose by the concentration on hand: 500 mg ÷ 250 mg/mL = 2 mL.
2. Furosemide IV Push
Question: The physician orders furosemide 40 mg IV push. Available is furosemide 10 mg/mL. How many mL will you administer?
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Answer: 4 mL
Rationale: 40 mg ÷ 10 mg/mL = 4 mL.
3. Acetaminophen Tablets
Question: The order is acetaminophen 650 mg PO. The pharmacy provides 325 mg tablets. How many tablets will you give?
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Answer: 2 tablets
Rationale: 650 mg ÷ 325 mg/tablet = 2 tablets.
4. Pediatric Amoxicillin mg/kg/day
Question: The child weighs 44 lb. The order is for amoxicillin 20 mg/kg/day in divided doses every 12 hours. How many mg per dose should the child receive?
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Answer: 200 mg per dose
Rationale: Convert pounds to kilograms: 44 lb ÷ 2.2 = 20 kg. Daily dose = 20 mg × 20 kg = 400 mg/day. The order is every 12 hours (2 doses per day), so 400 mg ÷ 2 = 200 mg per dose.
5. Heparin Subcutaneous Dose
Question: The order is heparin 5,000 units subcutaneously. The vial is labeled 10,000 units/mL. How many mL will you give? Answer: 0.5 mL Rationale: 5,000 units ÷ 10,000 units/mL = 0.5 mL.Show Answer and Rationale
6. IV Flow Rate mL/hr
Question: The IV order is for 1,000 mL normal saline to infuse over 8 hours. What is the flow rate in mL/hr? Answer: 125 mL/hr Rationale: 1,000 mL ÷ 8 hours = 125 mL/hr.Show Answer and Rationale
7. Dopamine mcg/kg/min Drip
Question: The order is dopamine 400 mg in 250 mL D5W to infuse at 5 mcg/kg/min. The client weighs 70 kg. How many mL/hr should be infused?
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Answer: 13 mL/hr
Rationale: Concentration: 400 mg ÷ 250 mL = 1.6 mg/mL = 1,600 mcg/mL. Required dose per minute: 5 mcg × 70 kg = 350 mcg/min. Volume per minute: 350 mcg ÷ 1,600 mcg/mL = 0.21875 mL/min. Per hour: 0.21875 × 60 = 13.125 ≈ 13 mL/hr.
8. Manual IV Drip Rate (gtt/min)
Question: The physician orders 500 mL of D5W to run over 4 hours. The drop factor is 15 gtt/mL. How many drops per minute should the IV be set to? Answer: 31 gtt/min Rationale: Total drops = 500 mL × 15 gtt/mL = 7,500 gtt. Time in minutes = 4 hours × 60 = 240 minutes. 7,500 ÷ 240 ≈ 31.25 ≈ 31 gtt/min.Show Answer and Rationale
9. Vancomycin IVPB Rate
Question: The order is vancomycin 1 g IV every 12 hours. The pharmacy sends 1 g in 250 mL to infuse over 2 hours. What is the rate in mL/hr? Answer: 125 mL/hr Rationale: 250 mL ÷ 2 hours = 125 mL/hr.Show Answer and Rationale
10. Digoxin Tablet Fraction
Question: The order is digoxin 0.125 mg PO. Tablets available are 0.25 mg each. How many tablets will you give? Answer: 0.5 tablet Rationale: 0.125 mg ÷ 0.25 mg/tablet = 0.5 tablet.Show Answer and Rationale
11. Magnesium Sulfate IVPB Rate
Question: The order is magnesium sulfate 2 g IVPB in 100 mL over 30 minutes. What is the flow rate in mL/hr?
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Answer: 200 mL/hr
Rationale: 30 minutes = 0.5 hour. 100 mL ÷ 0.5 hour = 200 mL/hr.
12. Pediatric Cefazolin Dose
Question: The child weighs 22 kg. The order is cefazolin 25 mg/kg/dose IV every 8 hours. How many milligrams per dose should the child receive? Answer: 550 mg Rationale: 25 mg × 22 kg = 550 mg per dose.Show Answer and Rationale
13. Potassium Chloride IVPB Rate
Question: The order is potassium chloride 20 mEq in 100 mL normal saline to run over 1 hour. What is the rate in mL/hr? Answer: 100 mL/hr Rationale: 100 mL ÷ 1 hour = 100 mL/hr.Show Answer and Rationale
14. Morphine IV Dose Volume
Question: The order is morphine 4 mg IV every 3 hours as needed. The vial is labeled 10 mg/mL. How many mL will you administer per dose? Answer: 0.4 mL Rationale: 4 mg ÷ 10 mg/mL = 0.4 mL.Show Answer and Rationale
15. Ceftriaxone IVPB Rate
Question: The order is ceftriaxone 1 g IVPB in 50 mL to infuse over 30 minutes. What is the rate in mL/hr?
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Answer: 100 mL/hr
Rationale: 30 minutes = 0.5 hour. 50 mL ÷ 0.5 hour = 100 mL/hr.
16. Lactated Ringer’s Drip (gtt/min)
Question: The order is to infuse 1,000 mL lactated Ringer’s over 6 hours using IV tubing with a drop factor of 20 gtt/mL. How many gtt/min will you set? Answer: 56 gtt/min Rationale: Total drops = 1,000 mL × 20 gtt/mL = 20,000 gtt. Time in minutes = 6 hours × 60 = 360 minutes. 20,000 ÷ 360 ≈ 55.6 ≈ 56 gtt/min.Show Answer and Rationale
17. Lidocaine Drip Rate
Question: The order is lidocaine 1 mg/min. The IV solution contains 2 g in 500 mL. What rate in mL/hr should you set on the pump? Answer: 15 mL/hr Rationale: 2 g = 2,000 mg; concentration = 2,000 mg ÷ 500 mL = 4 mg/mL. Dose per hour = 1 mg/min × 60 min = 60 mg/hr. 60 mg/hr ÷ 4 mg/mL = 15 mL/hr.Show Answer and Rationale
18. Converting g to mg for Volume
Question: The order is to give 600 mg of a medication. The vial is labeled 1.2 g/3 mL. How many mL will you administer?
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Answer: 1.5 mL
Rationale: 1.2 g = 1,200 mg. 600 mg is half of 1,200 mg, so the nurse needs half of 3 mL: 3 mL × 0.5 = 1.5 mL.
19. Phenytoin Capsules
Question: The order is phenytoin 300 mg PO at bedtime. Available are 100 mg capsules. How many capsules will you give? Answer: 3 capsules Rationale: 300 mg ÷ 100 mg/capsule = 3 capsules.Show Answer and Rationale
20. Pediatric Ibuprofen Single Dose
Question: The child weighs 33 lb. The order is ibuprofen 10 mg/kg as a single dose. How many mg should be administered?
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Answer: 150 mg
Rationale: 33 lb ÷ 2.2 ≈ 15 kg. 10 mg × 15 kg = 150 mg.
21. Total Volume Infused
Question: The IV is running at 75 mL/hr and will infuse for 8 hours. How much total volume will be infused? Answer: 600 mL Rationale: 75 mL/hr × 8 hours = 600 mL.Show Answer and Rationale
22. Metoclopramide IV Dose Volume
Question: The order is metoclopramide 10 mg IV push. On hand is 5 mg/mL. How many mL will you draw up?
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Answer: 2 mL
Rationale: 10 mg ÷ 5 mg/mL = 2 mL.
23. Converting Grams to Tablets
Question: The provider orders 0.5 g of a medication. Available are 250 mg tablets. How many tablets should be given? Answer: 2 tablets Rationale: 0.5 g = 500 mg. 500 mg ÷ 250 mg/tablet = 2 tablets.Show Answer and Rationale
24. Basic IV Infusion Rate
Question: The order is to infuse 500 mL of normal saline over 4 hours. What is the infusion rate in mL/hr?
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Answer: 125 mL/hr
Rationale: 500 mL ÷ 4 hours = 125 mL/hr.
25. Gentamicin mg/kg Dose
Question: The order is gentamicin 2 mg/kg IV every 8 hours. The patient weighs 70 kg. How many mg per dose should be administered? Answer: 140 mg Rationale: 2 mg × 70 kg = 140 mg per dose.Show Answer and Rationale
