To calculate intravenous flow rates, use the IV flow rate formula, which is volume in milliliters divided by the time in minutes, times the drop factor, explains Assessment Technologies Institute. Correctly calculating the IV flow rates ensures that fluids infuse at the prescribed rate.
Regardless of the whether the fluids are infused by manual control or by an infusion pump, the person administering the fluids must calculate the correct IV flow rate, notes Assessment Technologies Institute. The equipment that does factor into calculating IV flow rates is the type of intravenous tubing, specifically whether it is a micro-drip or macro-drip tube. For example, a provider orders 1000 mL of a fluid to infuse over eight hours, with a macro-drip tube, which has a drop factor of 15 drops per milliliter. One thousand milliliters is divided by eight hours, or 480 minutes, and multiplied by 15 drops per milliliter, which results in an IV flow rate of 31.2 drops per minute.