How Do Nurses Use Math in Their Jobs?

Math formulas are used to calculate the correct dose.

Math formulas are used to calculate the correct dose.

Math might not be the first skill that comes to mind when you think about a nursing career. People interested in this career should familiarize themselves with those math concepts generally used in nursing such as fractions, ratios, proportions, solutions and equations. Although nurses need many skills, math is a critical skill, used regularly for calculating medication dosage and programming IV drips.


Medications and solutions can be measured using a variety of measurement systems -- metric and apothecary, to name a couple. There is not one industry standard, so nurses use math to convert between these systems, using the shortest number of steps. Nurses memorize conversion tables and commonly used measurement abbreviations. They use the rules of Roman numerals, fractions, decimals, subtraction, addition, number rounding and conversion factors to solve ratios. To find conversions, nurses must be able to solve for x and find the unknown measurement.

IV Drip

Math is used to calculate the flow rates for an IV. Nurses use math to calculate how much IV fluid to administer per hour, how many drops per minute, how much medication should be in the IV and how much medication should be dispersed in a given time period. These problems are solved using formulas that involve division and rounding numbers. Nurses must know the correct IV formula to use for the problem and plug in the information that is known to get an answer.


Generally medication does not come in the same dosage being prescribed. For example, a patient may be prescribed 100 mg of a medication, but it is only available in 50 mg tablets. Proportions can be used to calculate the needed dosage. Units need to be converted to equals and then a simple calculation is used to solve for x. The problem is solved as a proportion, where units must be the same horizontally and you cross multiply to solve for x. Nurses also use math to calculate the medication dosage based on the patient's weight using conversions and a proportion to solve for x.

Pediatric Medications

Nurses use math to calculate pediatric doses. Pediatric doses are calculated by first converting the child's weight into kilograms. The weight is taken in pounds and then converted to kilograms, rounded to the nearest hundredth. Once the weight has been converted, nurses must solve the math formula to calculate the correct dosage. The information is put into the formula and using cross-multiplication, they solve for x, where x equals the dosage.


About the Author

Sara Mahuron specializes in adult/higher education, parenting, budget travel and personal finance. She earned an M.S. in adult/organizational learning and leadership, as well as an Ed.S. in educational leadership, both from the University of Idaho. Mahuron also holds a B.S. in psychology and a B.A. in international studies-business and economics.

Photo Credits

  • Comstock/Comstock/Getty Images