Dosage Calculation Practice Problems
This is a free set of 15 dosage calculation practice problems, the kind every nursing program tests before it lets you near a medication cart. It covers tablets and capsules, liquid oral doses, weight-based pediatric dosing with a safe range check, IV pump rates, drip rates with a drop factor, unit conversions, reconstitution and a heparin drip. Work all 15, then check your score and read the explanation for every problem.
The order is digoxin 0.25 mg PO daily. The pharmacy supplies 0.125 mg tablets. How many tablets do you give?
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All 15 questions at a glance
Prefer to read before you play? Every question in the sampler is listed below. Answers and explanations stay collapsed until you open them.
1. The order is digoxin 0.25 mg PO daily. The pharmacy supplies 0.125 mg tablets. How many tablets do you give?
- A. 0.5 tablets
- B. 1 tablet
- C. 2 tablets
- D. 4 tablets
Show answer and explanation
Answer: C. 2 tablets
Divide what is ordered by what is available: 0.25 mg divided by 0.125 mg per tablet gives 2 tablets. Getting 0.5 means the fraction was flipped, so always put the ordered dose on top and the strength you have on the bottom.
2. The order is 0.5 g PO. The drug is stocked as 250 mg capsules. How many capsules do you give?
- A. 1 capsule
- B. 2 capsules
- C. 4 capsules
- D. 20 capsules
Show answer and explanation
Answer: B. 2 capsules
Convert to one unit first: 0.5 g is 500 mg, and 500 mg divided by 250 mg per capsule is 2 capsules. Answering 1 capsule means 0.5 g was read as 250 mg, which is the classic error when the order and the label use different units.
3. Complete the conversion.
An order written as 1.5 g is the same dose as _____ mg.
Options for blank 1: 15, 150, 1500, 15,000
Show answer and explanation
Answer: 1500
There are 1,000 mg in 1 g, so moving from grams to milligrams multiplies by 1,000 and 1.5 g becomes 1,500 mg. Going the other way divides by 1,000, and the decimal moves three places, never one or two.
4. The order is amoxicillin 400 mg PO. The bottle reads 250 mg per 5 mL. How many mL do you draw up?
- A. 3.1 mL
- B. 5 mL
- C. 8 mL
- D. 12.5 mL
Show answer and explanation
Answer: C. 8 mL
Set it up as ordered divided by available, times the volume that holds it: 400 divided by 250, times 5 mL, gives 8 mL. The 3.1 mL answer comes from dividing 250 by 400, which is the same fraction upside down.
5. Which of these conversions are correct?
Select all that apply.
- A. 0.75 g equals 750 mg
- B. 500 mcg equals 0.5 mg
- C. 2.5 L equals 250 mL
- D. 66 lb equals 145 kg
- E. 1 teaspoon equals 5 mL
Show answer and explanation
Answer: A. 0.75 g equals 750 mg, B. 500 mcg equals 0.5 mg, E. 1 teaspoon equals 5 mL
Grams to milligrams, milligrams to micrograms and liters to milliliters all move by a factor of 1,000, so 2.5 L is 2,500 mL, not 250 mL. Pounds convert to kilograms by dividing by 2.2, so 66 lb is 30 kg, and multiplying by 2.2 instead is the single most expensive mistake in weight-based dosing.
6. A child weighs 44 lb. The order is 15 mg/kg per dose. What is the dose in mg?
- A. 150 mg
- B. 300 mg
- C. 660 mg
- D. 1,452 mg
Show answer and explanation
Answer: B. 300 mg
Convert the weight first: 44 lb divided by 2.2 is 20 kg, and 20 kg times 15 mg/kg is 300 mg. The 660 mg answer uses pounds directly and the 1,452 mg answer multiplies by 2.2 instead of dividing, and both would be a large overdose in a child.
7. A child weighs 25 kg. The safe range for the ordered drug is 10 to 20 mg/kg per dose, and the prescriber has written 500 mg every 6 hours. Which statements are correct?
Select all that apply.
- A. The safe range for this child is 250 to 500 mg per dose
- B. The ordered dose sits at the top of the safe range, so it may be given
- C. Given every 6 hours, the ordered dose totals 2,000 mg in 24 hours
- D. The ordered dose is above the safe range and must be held
- E. The safe range for this child is 100 to 200 mg per dose
Show answer and explanation
Answer: A. The safe range for this child is 250 to 500 mg per dose, B. The ordered dose sits at the top of the safe range, so it may be given, C. Given every 6 hours, the ordered dose totals 2,000 mg in 24 hours
Multiply the weight by each end of the range: 25 kg times 10 mg/kg is 250 mg and 25 kg times 20 mg/kg is 500 mg, so the ordered dose is at the ceiling but still inside the range. Every 6 hours means four doses a day, so also check the 24 hour total against the drug's daily maximum, because a dose can be safe on its own and unsafe when repeated.
8. A child weighs 16 kg. The order is acetaminophen 15 mg/kg per dose, and the bottle reads 160 mg per 5 mL. How many mL do you give?
- A. 3.3 mL
- B. 5 mL
- C. 7.5 mL
- D. 12 mL
Show answer and explanation
Answer: C. 7.5 mL
Work it in two steps: 16 kg times 15 mg/kg is 240 mg, then 240 divided by 160, times 5 mL, is 7.5 mL. Doing it in one line without writing the 240 mg down is where students lose track, and the 3.3 mL answer is the same numbers with the fraction inverted.
9. Complete the conversion.
A dose of 250 mcg is the same as _____ mg.
Options for blank 1: 0.025, 0.25, 2.5, 25
Show answer and explanation
Answer: 0.25
There are 1,000 mcg in 1 mg, so 250 mcg divided by 1,000 is 0.25 mg. Write the leading zero before the decimal point and never a trailing zero after it, because 0.25 misread as 25 is a hundredfold overdose.
10. An IV medication in 250 mL is to infuse over 90 minutes on a pump. What rate do you set, in mL/hr?
- A. 2.8 mL/hr
- B. 150 mL/hr
- C. 167 mL/hr
- D. 375 mL/hr
Show answer and explanation
Answer: C. 167 mL/hr
A pump wants mL per hour, so convert 90 minutes to 1.5 hours and divide: 250 divided by 1.5 is 166.7, which rounds to 167 mL/hr. Dividing by 90 instead of 1.5 gives 2.8, which is mL per minute territory and should look obviously wrong for a bag meant to run in an hour and a half.
11. 1,000 mL of normal saline is ordered over 10 hours by gravity, using tubing with a drop factor of 15 gtt/mL. What is the drip rate in gtt/min?
- A. 15 gtt/min
- B. 25 gtt/min
- C. 100 gtt/min
- D. 1,500 gtt/min
Show answer and explanation
Answer: B. 25 gtt/min
First find the hourly rate, 1,000 mL divided by 10 hours is 100 mL/hr, then multiply by the drop factor and divide by 60 minutes: 100 times 15 divided by 60 is 25 gtt/min. Answering 100 means the drop factor was skipped, so the number reported was really the mL/hr rate wearing the wrong unit.
12. Complete the sentence.
With microdrip tubing that has a drop factor of 60 gtt/mL, the drip rate in gtt/min is always equal to the _____.
Options for blank 1: rate in mL/hr, number of hours the bag runs, drop factor itself, total volume in the bag
Show answer and explanation
Answer: rate in mL/hr
The formula multiplies by the drop factor and divides by 60 minutes, so with 60 gtt/mL those two cancel and the gtt/min number matches the mL/hr number. This only works at 60 gtt/mL, so with macrodrip tubing at 10, 15 or 20 gtt/mL you still have to run the full calculation.
13. A vial of powdered antibiotic says to add 3.4 mL of diluent to yield a concentration of 250 mg/mL. The order is 750 mg. How many mL do you withdraw?
- A. 2.5 mL
- B. 3 mL
- C. 3.4 mL
- D. 4 mL
Show answer and explanation
Answer: B. 3 mL
Reconstitution is a two-part label: the diluent volume tells you what to inject into the vial, and the concentration tells you what to draw out, so 750 mg divided by 250 mg/mL is 3 mL. Choosing 3.4 mL uses the diluent volume as the dose, which is a different number because the powder itself takes up space once it dissolves.
14. Heparin is ordered at 1,200 units/hr. The bag contains 25,000 units in 500 mL of D5W. What pump rate do you set, in mL/hr?
- A. 12 mL/hr
- B. 24 mL/hr
- C. 48 mL/hr
- D. 60 mL/hr
Show answer and explanation
Answer: B. 24 mL/hr
Find the concentration first: 25,000 units divided by 500 mL is 50 units/mL, so 1,200 units/hr divided by 50 units/mL is 24 mL/hr. The 48 mL/hr answer assumes 25 units/mL, which is what you get if the bag volume is read as 1,000 mL, and heparin is a high alert drug where that error is a bleeding event.
15. Which of the following belong in a safe, repeatable dose calculation method?
Select all that apply.
- A. Write every value with its unit and cancel the units through the setup
- B. Have a second nurse independently check high alert drugs such as insulin and heparin
- C. Ask whether the answer is reasonable before giving it, for example more than three tablets for one dose
- D. Round every answer to a whole number so the math stays simple
- E. Skip the safe range check when a prescriber has already written the order
Show answer and explanation
Answer: A. Write every value with its unit and cancel the units through the setup, B. Have a second nurse independently check high alert drugs such as insulin and heparin, C. Ask whether the answer is reasonable before giving it, for example more than three tablets for one dose
Carrying units through the setup and sanity checking the result catch most calculation errors before they reach the patient, and an independent double check is standard for high alert drugs like insulin and heparin. Rounding is set by your program and the device, not by convenience, and the nurse who gives the dose is still responsible for checking that an order is within the safe range.
What dosage calculation exams actually ask
Almost every nursing program runs a dosage calculation exam, often called a med math or drug calc exam, and most of them require a very high score to pass. Passing scores of 90 percent or 100 percent are common, and many programs give you two or three attempts before it affects your standing in the course. The exact passing score, the time limit, whether a calculator is allowed and how many attempts you get are all set by your program, so check your own syllabus rather than a number you read on a forum.
The question types are far more consistent than the rules around them. You will be asked for tablets or capsules per dose, the volume of a liquid oral dose, a weight-based pediatric dose in mg/kg with a check against a safe range, an IV pump rate in mL/hr, a drip rate in gtt/min using the tubing's drop factor, a unit conversion between mg and g or mcg and mg or pounds and kilograms, a reconstitution problem where you read the concentration off the vial label, and at least one high alert drug such as heparin or insulin. The same handful of setups covers nearly the whole exam.
Rounding is the detail that varies most and costs the most points. Some programs want tablets rounded to the nearest half, mL to the nearest tenth and gtt/min to a whole number, while others round mL to whole numbers for volumes over 1 mL. Drop factors vary too: macrodrip tubing is commonly 10, 15 or 20 gtt/mL and microdrip tubing is 60 gtt/mL, and the problem has to tell you which one you are using. Write your program's rounding rules on the front of your notes and use them every single time you practice.
How to use these practice problems
A wrong dose is a patient safety event, not a lost point. That is the reason these exams are graded so harshly, and it is also the reason the goal here is a repeatable method rather than speed. A nurse who works every problem the same way, with the units written out, catches their own mistakes. A nurse who does them in their head quickly does not.
Use one setup for everything: write what is ordered, write what is available with its units, cancel the units through the equation, and only then look at the number. Label every value, including the weight in kilograms and the drop factor. When you have an answer, ask whether it is reasonable before you accept it. More than two or three tablets for one dose, a pediatric dose larger than an adult dose, or a drip rate in the hundreds of gtt/min are all signs you inverted a fraction or dropped a conversion, and they should send you back to the setup.
The wrong answers in this sampler are not random. Each one is the result of a mistake nurses actually make: using pounds where the formula wants kilograms, multiplying by 2.2 instead of dividing, forgetting the drop factor so the gtt/min answer is really the mL/hr rate, drawing up the diluent volume printed on the vial instead of the volume that holds the ordered dose, or flipping the have and want values. If you land on one of those, read the explanation and name the mistake out loud. That is what stops it from happening again on a real patient.
How StudyPDF builds full practice tests from your own materials
Fifteen problems can show you which setup you are shaky on. They cannot get you to a 100 percent pass on their own, and a generic question bank has no idea which drugs, which drop factors and which rounding rules your program uses.
StudyPDF works from your material instead. You upload your dosage calculation workbook, your pharmacology notes or the practice packet your instructor handed out, and Bo, the study agent, builds full-length practice tests from those exact pages. Every question is grounded in your material, and every explanation cites where the answer comes from, so you can go back to the page when a step looks wrong. You can regenerate fresh tests as often as you like and narrow them to one setup, such as gtt/min or mg/kg, until it stops costing you points.
You do not need a document to start. You can also just name a topic, say IV flow rates or pediatric safe dose range, and Bo will build practice problems and worked explanations for it from scratch. That is useful when a problem here exposed a weak spot and you want twenty more of the same kind before you go looking for the right chapter. Starting is free.
Written by the StudyPDF team. Last updated 2026-08-19.