Drop factor = the number of drops it takes to make up one ml of solution. For most clear fluids, this is 20 drops per ml.
Drop rate = Volume of infusion in ml ÷ Time in minutes X Drop Factor
For example, if administrating an IVMT bag of 250ml in 30 mins, the drop rate should be calculated as: 250÷30 X20, which will result in 167 drops per minute.