Knowing how to calculate milligrams per hour is typically a skill necessary in calculating drug dosage for patients in medical environments. Nurses need to know how to compute basic formulas to administer drug dosage accurately. Erroneous calculations can have significant effects, which can lead to various health complications, on patients. For example, Nursing Times states that if patients are given excessive drug concentrations, such as local anesthetic, consequences may include immobility and pressure ulcers.

Determine the hourly flow rate. This is the rate of fluid volume, such as medicine, that passes or flows through per unit of time.

Determine the concentration of the solution in milligrams per milliliter.

Multiply the hourly flow rate of the liquid by the concentration. This will determine the milligrams per hour. The formula looks like this:

mg/hour=hourly flow rate x concentration