NCLEX Dosage Calculations Cheat Sheet
Page 1 – Introduction
Safe medication administration is one of the most critical responsibilities of a nurse.
Understanding dosage calculations is essential to prevent medication errors, ensure
patient safety, and pass the NCLEX exam.
This cheat sheet provides a step-by-step guide to mastering dosage calculations, covering
common formulas, conversions, and examples you will likely encounter on the NCLEX.
By the end of this book, you will be able to:
● Convert between units of measurement
● Calculate doses for tablets, liquids, and injections
● Determine IV flow rates
● Solve multi-step medication problems
Nurses who can accurately calculate dosages reduce the risk of errors, improve patient
outcomes, and gain confidence in clinical practice.
Page 2 – Basic Medication Math
Common Units of Measurement
, Unit Abbreviation Metric Equivalent
Milligram mg 1/1000 g
Gram g 1000 mg
Microgram mcg 1/1,000,000 g
Milliliter mL 1/1000 L
Liter L 1000 mL
Key Tips:
● Always double-check the units.
● Make sure the prescribed dose matches the form of the medication.
Formula Method (Basic)
Dose = (Desired / Available) × Quantity
● Desired = the dose ordered by the doctor
● Available = the dose strength available
● Quantity = the form in which medication comes (tablets, mL, etc.)
Example:
Order: 250 mg of medication
Available: 500 mg tablets
Dose = (250 ÷ 500) × 1 tablet = 0.5 tablet
Page 3 – IV Flow Rates
Drops per Minute (gtt/min)
Formula:
Flow Rate (gtt/min) = (Volume × Drop Factor) ÷ Time (minutes)
● Volume = total mL to infuse
● Drop factor = number of drops per mL (from IV tubing)
● Time = infusion time in minutes
Example:
1000 mL of IV fluid to run over 8 hours using 15 gtt/mL tubing
Page 1 – Introduction
Safe medication administration is one of the most critical responsibilities of a nurse.
Understanding dosage calculations is essential to prevent medication errors, ensure
patient safety, and pass the NCLEX exam.
This cheat sheet provides a step-by-step guide to mastering dosage calculations, covering
common formulas, conversions, and examples you will likely encounter on the NCLEX.
By the end of this book, you will be able to:
● Convert between units of measurement
● Calculate doses for tablets, liquids, and injections
● Determine IV flow rates
● Solve multi-step medication problems
Nurses who can accurately calculate dosages reduce the risk of errors, improve patient
outcomes, and gain confidence in clinical practice.
Page 2 – Basic Medication Math
Common Units of Measurement
, Unit Abbreviation Metric Equivalent
Milligram mg 1/1000 g
Gram g 1000 mg
Microgram mcg 1/1,000,000 g
Milliliter mL 1/1000 L
Liter L 1000 mL
Key Tips:
● Always double-check the units.
● Make sure the prescribed dose matches the form of the medication.
Formula Method (Basic)
Dose = (Desired / Available) × Quantity
● Desired = the dose ordered by the doctor
● Available = the dose strength available
● Quantity = the form in which medication comes (tablets, mL, etc.)
Example:
Order: 250 mg of medication
Available: 500 mg tablets
Dose = (250 ÷ 500) × 1 tablet = 0.5 tablet
Page 3 – IV Flow Rates
Drops per Minute (gtt/min)
Formula:
Flow Rate (gtt/min) = (Volume × Drop Factor) ÷ Time (minutes)
● Volume = total mL to infuse
● Drop factor = number of drops per mL (from IV tubing)
● Time = infusion time in minutes
Example:
1000 mL of IV fluid to run over 8 hours using 15 gtt/mL tubing
