Calculating Drop Factor with Gravity IV Infusions
• Identify the drop factor of your IV administration set (tubing) found on the label of the tubing package. Macrodrip sets are either 10, 15
or 20 drops to deliver 1 mL of fluid in a minute. Microdrip sets are commonly 60.
• Formula to calculate gravity flow rates:
o mL/hr divided by 60 minutes (I hour) x drop factor = drops/minute (rounded off)
Examples using Macrodrip drop factors:
A. IV fluid of 125mL/hr using tubing with drop factor of 10.
• 125mL/hr divided by 60 minutes = 2.08mL/min
• 2.08mL/min X 10 drop factor = 21 drops/min
B. IV fluid of 125mL/hr using tubing with drop factor of 15.
• 125mL/hr divided by 60 minutes (1 hour) =
2.08mL/min
• 2.08mL/min X 15 drop factor = 31 drops/min
C. IV fluid of 125mL/hr using tubing with drop factor of 20.
• 125mL/hr divided by 60 minutes = 2.08mL/min
• 2.08mL/min X 20 drop factor = 42 drops/min
• Confirm/monitor the gravity infusion rate for accuracy; Flow control devices (dial a flow) do NOT replace this responsibility.
• Count the drops/minute for a full minute when infusing by gravity and setting the clamp/confirming the drip rate.
Common drops/minute for infusions using 10 drop factor tubing (Continu-Flo Solution Set 2C8537):
150mL/hr = 25 drops/min
75mL/hr = 13 (12.5) drops/min
125mL/hr = 21 (20.8) drops/min
50mL/hr = 8 (8.3) drops/min
100mL/hr = 17 (16.6) drops/min
25mL/hr = 4 (4.1) drops/min
Count for 1 full minute:
One drip!!! HAHAHA…
Two drips!!! HAHAHA…
Three drips!!! HAHAHA!!…
