IV Fluid Infusion Rate Calculator
Infusion Results
Flow Rate
—
mL / hour
Drip Rate
—
gtt / min
Understanding the IV Fluid Infusion Rate Calculation
In clinical settings, calculating the intravenous (IV) infusion rate accurately is critical for patient safety. Whether you are using an infusion pump or a gravity drip, you must know how much fluid to administer over a specific period. This calculator helps healthcare professionals determine both the hourly flow rate (mL/hr) and the drip rate (drops per minute).
The IV Infusion Formulas
There are two primary formulas used based on the equipment available:
Flow Rate (mL/hr) = Total Volume (mL) ÷ Time (hours)
Drip Rate (gtt/min) = [Total Volume (mL) × Drop Factor (gtt/mL)] ÷ Time (minutes)
Key Definitions
- Total Volume: The total amount of fluid or medication to be infused (usually in milliliters).
- Drop Factor: The number of drops (gtt) required to deliver 1 mL of fluid. This is determined by the administration set.
- Macro-drip: Typically 10, 15, or 20 gtt/mL.
- Micro-drip: Always 60 gtt/mL (standard for pediatric and high-precision medications).
- Time: The duration over which the infusion should occur.
Practical Calculation Example
Scenario: A physician orders 1,000 mL of Normal Saline to be infused over 8 hours. You are using a standard administration set with a drop factor of 20 gtt/mL.
Step 1: Calculate mL/hr
1,000 mL ÷ 8 hours = 125 mL/hr
Step 2: Calculate gtt/min
First, convert hours to minutes: 8 hours × 60 = 480 minutes.
(1,000 mL × 20 gtt/mL) ÷ 480 minutes = 20,000 ÷ 480 = 41.67 gtt/min (rounded to 42 gtt/min).