IV Rate Calculations
INFORMATION REQUIRED ON AN ORDER FOR IV FLUIDS
IV Administration Set Calibrations IV flow rates are regulated in drops per minute (gtts/min). The size of the drop (drop factor) varies from large to small, and depending on the manufacturer and type of set used, it will require 10, 15, or 20 gtts to equal 1 ml in standard macrodrip sets, and 60 gtts to equal 1 ml in micro or minidrip sets.

IV Drop Rate for
Note For IV's, round off to the nearest whole number. 
Example 1
The order is for D_{5½} NS 1000 ml to be infused over eight hours. Calculate the infusion rate using an IV set calibrated to deliver 20 gtts/ml.
1000 x
20 gtts = 41.67 or 42 gtts/min 8 x 60 min 1
Example 2
The patient is to receive 1000 ml of 0.45% sodium chloride over the next 10 hours. The drop factor of the tubing is 15 gtts/ml. Determine the rate in gtts/min.
1000 x
15 gtts = 25 gtts/min 10 x 60 min 1
IV Drop Rate Calculations for Continuous Infusion
With continuous I.V. infusions of medications, the physician will order a medication dosage and not fluid volume. For example, the order may specify mg/hr or units/hr.
Example 1
The order is to administer a continuous I.V. Heparin drip at a rate of 1200 units per hour. The pharmacy sends up a 250 ml bag of Normal Saline with 25,000 units of Heparin added. Using a drop factor of 60 gtts/ml, determine the infusion rate to deliver the ordered amount of medication.
1000 x
15 gtts = 25 gtts/min 10 x 60 min 1