NCLEX Dosage Calculation Practice
Updated October 26, 2026
Dosage calculation questions appear on the NCLEX within pharmacological and parenteral therapies. They’re very learnable: almost every problem uses one of a few formulas and conversions. Learn them below, then work the free problems. Each answer shows the steps.
Conversions
| From | To |
|---|---|
| 1 kg | 2.2 lb |
| 1 g | 1,000 mg |
| 1 mg | 1,000 mcg |
| 1 L | 1,000 mL |
| 1 tsp | 5 mL |
| 1 tbsp | 15 mL |
| 1 oz | 30 mL |
Formulas
Desired over have: amount to give = (desired dose ÷ dose on hand) × quantity. If 50 mg is ordered and tablets are 25 mg, give (50 ÷ 25) × 1 = 2 tablets.
Weight-based dose: dose = mg/kg × weight in kg. Convert pounds to kilograms first.
IV rate in mL per hour: total volume ÷ hours.
IV drip rate in drops per minute: (volume in mL × drop factor in gtt/mL) ÷ time in minutes.
Free dosage calculation practice
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An order calls for metoprolol 50 mg by mouth. Tablets on hand are 25 mg. How many tablets should the nurse give?Answer: CDesired over have: 50 mg ÷ 25 mg = 2, times 1 tablet = 2 tablets.
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A child weighs 33 lb. The order is 15 mg/kg of a medication. How many mg should the child receive?Answer: AConvert to kilograms: 33 ÷ 2.2 = 15 kg. Then 15 kg × 15 mg/kg = 225 mg.
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1,000 mL of normal saline is ordered over 8 hours. What is the infusion rate in mL per hour?Answer: CDivide the volume by the time: 1,000 mL ÷ 8 hours = 125 mL/hr.
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An IV of 500 mL is to run over 4 hours using tubing with a drop factor of 15 gtt/mL. What is the drip rate in drops per minute? (Round to the nearest whole number.)Answer: A(500 mL × 15 gtt/mL) ÷ (4 × 60 min) = 7,500 ÷ 240 = 31.25, which rounds to 31 drops per minute.
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An order is for 0.125 mg of digoxin. How many micrograms is that?Answer: D1 mg = 1,000 mcg, so 0.125 mg × 1,000 = 125 mcg.
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Amoxicillin oral suspension is available as 250 mg/5 mL. The order is 500 mg. How many mL should be given?Answer: BDesired over have: (500 mg ÷ 250 mg) × 5 mL = 2 × 5 mL = 10 mL.
Tips
Write the units at every step and cancel them, so you can see when a setup is wrong. Round only at the end, and follow the question’s rounding instruction. Then ask whether the answer is reasonable: giving 10 tablets of one drug is almost never right.
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