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Pharmacy Technician Math Practice for the PTCB Exam

Updated October 27, 2026

Pharmacy math shows up throughout the PTCE, especially in Order Entry and Processing, which is 22.5% of the exam. Most problems use the same handful of conversions and two or three methods. Learn the table below, then work the free practice problems. Each answer shows the setup.

Conversions to memorize

From To
1 kilogram (kg) 2.2 pounds (lb)
1 gram (g) 1,000 milligrams (mg)
1 milligram (mg) 1,000 micrograms (mcg)
1 liter (L) 1,000 milliliters (mL)
1 teaspoon (tsp) 5 mL
1 tablespoon (tbsp) 15 mL
1 fluid ounce (fl oz) 30 mL (29.57 mL exactly)
1 grain (gr) 65 mg (64.8 mg exactly)

The methods

Ratio and proportion. Set up two equal ratios with the same units on top and bottom, then cross-multiply. If 250 mg is in 5 mL, then x mg in 15 mL: 250⁄5 = x/15, so x = 750 mg.

Days supply. Days supply = total quantity dispensed ÷ quantity used per day.

Percent strength. For a solution, a percentage means grams per 100 mL (weight in volume). A 5% solution has 5 g in every 100 mL.

Alligation. Used to mix a higher and a lower strength to make one in between. Subtract diagonally to get the parts of each. See the last practice problem.

Free pharmacy math practice problems

  1. A patient weighs 154 pounds. What is the patient's weight in kilograms?
  2. A prescription reads: amoxicillin 250 mg/5 mL, take 2 teaspoons by mouth three times a day for 10 days. How many mL should be dispensed?
  3. An order calls for 375 mg of a drug available as 125 mg/5 mL. How many mL are needed for one dose?
  4. A prescription for 90 tablets reads: take 1 tablet three times a day. What is the days supply?
  5. How many grams of dextrose are in 500 mL of a 5% dextrose solution?
  6. A dose of 0.25 mg is ordered. How many micrograms is that?
  7. A child weighs 44 lb. The dose is 10 mg/kg per day, divided into two doses. How many mg is each dose?
  8. How many parts of a 10% cream and a 2% cream are needed to make a 5% cream?
  9. A prescription reads: 1 tablespoon by mouth twice a day for 7 days. How many mL should be dispensed?
  10. An inhaler contains 200 puffs. The directions are 2 puffs four times a day. What is the days supply?
  11. Convert 3 grains to milligrams (1 grain = 65 mg).
  12. A patient needs 1.5 g of a drug. Capsules are 500 mg each. How many capsules is one dose?
  13. An insulin vial is labeled U-100. How many units are in 0.4 mL?
  14. A prescription for 60 tablets reads: take 2 tablets daily for 3 days, then 1 tablet daily. What is the days supply?
  15. A drug costs $45 for 30 tablets. What is the cost of 12 tablets?
  16. Convert 98.6°F to Celsius. (°C = (°F − 32) × 5/9)

Tips

Write the units at every step, and they’ll tell you whether the setup is right. Check that the answer makes sense: a child’s dose should be smaller than an adult’s, and a days supply is a whole number of days (round down for a partial day).

Pass the PTCB exam on your first try

  • All 194 questions across medications, federal requirements, patient safety and order entry
  • An explanation for every answer, with the law, standard or label behind it
  • Unlimited full 90-question practice exams, with each domain in its real share
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Pass the PTCB exam on your first try.

  • All 194 questions across medications, federal requirements, patient safety and order entry
  • An explanation for every answer, with the law, standard or label behind it
  • Unlimited full 90-question practice exams, with each domain in its real share
  • Practice exams for each knowledge domain

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