Gravity Infusion Rate Calculator
Calculate IV flow rates (gtt/min) for manual gravity drips
Infusion Parameters
Total amount of fluid to be infused.
Total time for the infusion.
Check your IV tubing packaging.
Required Flow Rate
Enter parameters to calculate drop rate
How to Calculate Gravity Infusion Rates
In clinical settings where electronic infusion pumps are unavailable or not required, nurses must manually regulate IV fluid administration using gravity. The Gravity Infusion Rate Calculator helps medical professionals determine the correct "drops per minute" (gtt/min) to set the roller clamp on the IV tubing.
The Drop Rate Formula
To calculate the flow rate manually, you need three pieces of information: total volume, time, and the drop factor of your tubing. The standard formula used in nursing is:
Since orders are typically written in hours, you usually convert the hours to minutes by multiplying by 60.
Understanding Drop Factors
The "Drop Factor" refers to how many drops it takes to equal 1 mL of fluid. This is determined by the tubing manufacturer and is printed on the package.
- Macrodrip Sets (10, 15, or 20 gtt/mL): Used for general IV therapy, rapid fluid replacement, or thicker fluids. The tubing creates larger drops.
- Microdrip Sets (60 gtt/mL): Used for precise medication administration, pediatrics, or slow infusion rates. The tubing includes a needle that creates very small drops. Note: In microdrip sets, 60 gtt/min equals 60 mL/hr.
Example Calculation
A patient is prescribed 1,000 mL of Normal Saline to infuse over 8 hours. The available tubing is a standard macrodrip set with a drop factor of 15 gtt/mL.
- Convert time to minutes: 8 hours × 60 = 480 minutes.
- Multiply volume by drop factor: 1,000 mL × 15 = 15,000.
- Divide by minutes: 15,000 ÷ 480 = 31.25.
- Round to the nearest whole number: 31 gtt/min.
Disclaimer: This tool is for educational and verification purposes only. Always double-check calculations according to your facility's protocols before administering medication or fluids.