IV Drip Rate Calculator
Calculate intravenous drip rate in drops per minute (gtt/min) and flow rate in mL/hr for gravity IV infusions with different drop factor giving sets.
Results
What is it?
DISCLAIMER: For educational and reference purposes only. All clinical decisions must be made by qualified healthcare professionals. The IV drip rate formula calculates how many drops per minute a gravity IV infusion must run to deliver the prescribed volume over the prescribed time. The formula is: Drip rate (gtt/min) = [Volume (mL) x Drop Factor (gtt/mL)] / Time (min). This is used for gravity sets where an infusion pump is not available. Modern IV pumps use mL/hr — always prefer electronic infusion pumps where available for precision.
How to use
Enter the total volume to be infused in mL, the infusion duration in hours, and the drop factor of the giving set (printed on the packaging — commonly 10, 15, 20, or 60 gtt/mL). The calculator outputs the rounded drops per minute for clinical use and the exact mL/hr flow rate.
Example scenario
1,000 mL of normal saline over 8 hours using a 20 gtt/mL giving set. Time = 8 x 60 = 480 minutes. Flow rate = 1,000 / 8 = 125 mL/hr. Drip rate = (1,000 x 20) / 480 = 41.67, rounded to 42 gtt/min.
Pro tip
Count drops for 15 seconds and multiply by 4 to verify the drip rate at the bedside. Gravity infusion rates drift over time as the bag empties and pressure changes — recheck every 30-60 minutes. For viscous fluids (blood products, certain antibiotics), use the appropriate blood giving set (10 gtt/mL) and follow local infusion protocols.