gtt/min to mL/hr Calculator
Enter the observed drip rate in drops per minute.
Drop factor is printed on your IV tubing packaging.
Results are approximate. Always verify against medical order and local protocols.
Written by George Lambroglou, RN • Last reviewed 21 Jun 2026
Convert an observed gravity drip rate in drops per minute (gtt/min) back to the equivalent hourly infusion rate in mL/hr.
Formula
mL/hr = (gtt/min ÷ drop factor) × 60
Worked Example
Observed drip rate: 40 gtt/min. Drop factor: 20 gtt/mL. What is the rate in mL/hr?
mL/min = 40 ÷ 20 = 2 mL/min
mL/hr = 2 × 60 = 120 mL/hr
mL/hr = 2 × 60 = 120 mL/hr
Answer: 120 mL/hr
Safety note: Always confirm the drop factor printed on your giving set before converting. Using the wrong drop factor will give an incorrect result.