Liquid and injection dosage calculation practice problems

Dosage calculation practice for nursing students: solve unlimited new problems below with instant checking, or work through the 15 problems with answers further down.

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Formula to use

mL = desired dose ÷ dose on hand × volume on hand (mL)

D ÷ H × Q

Open the liquid medication and injection dosage (ml) calculator to check your own numbers step by step.

15 practice problems with answers

Solve each problem on paper first, then open the answer to compare every step.

Order: morphine 2 mg IV push. Available: morphine injection 4 mg/mL. How many mL will you draw up?
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1. mL = desired ÷ have × quantity = 2 ÷ 4 × 1 mL = 0.5 mL.
2. Less than 1 mL: round to the hundredth, 0.5 mL (1 mL syringe).
Answer: 0.5 mL
Order: ketorolac 15 mg IV push. Available: ketorolac injection 30 mg/mL. How many mL will you draw up?
Show the answer
1. mL = desired ÷ have × quantity = 15 ÷ 30 × 1 mL = 0.5 mL.
2. Less than 1 mL: round to the hundredth, 0.5 mL (1 mL syringe).
Answer: 0.5 mL
Order: furosemide 40 mg IV push. Available: furosemide injection 10 mg/mL. How many mL will you draw up?
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1. mL = desired ÷ have × quantity = 40 ÷ 10 × 1 mL = 4 mL.
2. Round to the tenth: 4 mL.
Answer: 4 mL
Order: promethazine 12.5 mg deep IM. Available: promethazine injection 25 mg/mL. How many mL will you draw up?
Show the answer
1. mL = desired ÷ have × quantity = 12.5 ÷ 25 × 1 mL = 0.5 mL.
2. Less than 1 mL: round to the hundredth, 0.5 mL (1 mL syringe).
Answer: 0.5 mL
Order: acetaminophen 240 mg PO. Available: acetaminophen oral suspension 160 mg per 5 mL. How many mL will you give?
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1. mL = desired ÷ have × quantity = 240 ÷ 160 × 5 mL = 7.5 mL.
2. Round to the tenth: 7.5 mL.
Answer: 7.5 mL
Order: acetaminophen 320 mg PO. Available: acetaminophen oral suspension 160 mg per 5 mL. How many mL will you give?
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1. mL = desired ÷ have × quantity = 320 ÷ 160 × 5 mL = 10 mL.
2. Round to the tenth: 10 mL.
Answer: 10 mL
Order: dexamethasone 6 mg IV push. Available: dexamethasone injection 4 mg/mL. How many mL will you draw up?
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1. mL = desired ÷ have × quantity = 6 ÷ 4 × 1 mL = 1.5 mL.
2. Round to the tenth: 1.5 mL.
Answer: 1.5 mL
Order: famotidine 20 mg IV push. Available: famotidine injection 10 mg/mL. How many mL will you draw up?
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1. mL = desired ÷ have × quantity = 20 ÷ 10 × 1 mL = 2 mL.
2. Round to the tenth: 2 mL.
Answer: 2 mL
Order: diphenhydramine 25 mg IV push. Available: diphenhydramine injection 50 mg/mL. How many mL will you draw up?
Show the answer
1. mL = desired ÷ have × quantity = 25 ÷ 50 × 1 mL = 0.5 mL.
2. Less than 1 mL: round to the hundredth, 0.5 mL (1 mL syringe).
Answer: 0.5 mL
Order: furosemide 20 mg IV push. Available: furosemide injection 10 mg/mL. How many mL will you draw up?
Show the answer
1. mL = desired ÷ have × quantity = 20 ÷ 10 × 1 mL = 2 mL.
2. Round to the tenth: 2 mL.
Answer: 2 mL
Order: ondansetron 4 mg IV push. Available: ondansetron injection 2 mg/mL. How many mL will you draw up?
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1. mL = desired ÷ have × quantity = 4 ÷ 2 × 1 mL = 2 mL.
2. Round to the tenth: 2 mL.
Answer: 2 mL
Order: amoxicillin 375 mg PO. Available: amoxicillin oral suspension 250 mg per 5 mL. How many mL will you give?
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1. mL = desired ÷ have × quantity = 375 ÷ 250 × 5 mL = 7.5 mL.
2. Round to the tenth: 7.5 mL.
Answer: 7.5 mL
Order: cyanocobalamin 1 mg IM. Available: cyanocobalamin injection 1,000 mcg/mL. How many mL will you draw up?
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1. Convert: 1 mg = 1,000 mcg.
2. mL = desired ÷ have × quantity = 1,000 ÷ 1,000 × 1 mL = 1 mL.
3. Round to the tenth: 1 mL.
Answer: 1 mL
Order: haloperidol lactate 2.5 mg IM. Available: haloperidol lactate injection 5 mg/mL. How many mL will you draw up?
Show the answer
1. mL = desired ÷ have × quantity = 2.5 ÷ 5 × 1 mL = 0.5 mL.
2. Less than 1 mL: round to the hundredth, 0.5 mL (1 mL syringe).
Answer: 0.5 mL
Order: lorazepam 1 mg IV push. Available: lorazepam injection 2 mg/mL. How many mL will you draw up?
Show the answer
1. mL = desired ÷ have × quantity = 1 ÷ 2 × 1 mL = 0.5 mL.
2. Less than 1 mL: round to the hundredth, 0.5 mL (1 mL syringe).
Answer: 0.5 mL