Step 1: Convert inputs to common units.
Step 2: Solve equation.
gtt/min = (V × DF) / T
gtt/min = (1000 × 15) / 480
Result = 31.3 gtt/min
Enter the volume, infusion time, and drop factor above to instantly calculate the IV flow rate in gtt/min and mL/hr.
Calculate IV Flow RateIntravenous (IV) flow rate calculations ensure patients receive fluids and medications at the correct speed. The formula accounts for the total volume to infuse, the time frame, and the drip calibration of the IV tubing.
The drop factor (gtt/mL) is printed on the IV tubing package. Macro drip sets (10, 15, or 20 gtt/mL) are used for larger volumes, while micro drip sets (60 gtt/mL) provide precise control for smaller volumes or pediatric patients.
Order: Infuse 1,000 mL Normal Saline over 8 hours using a 15 gtt/mL drip set.
Flow Rate = (1000 × 15) / 480 = 31.25 gtt/min
mL/hr = 1000 / 8 = 125 mL/hr
| Type | Drop Factor | Common Use |
|---|---|---|
| Macro drip | 10 gtt/mL | Blood products, large-volume infusions |
| Macro drip | 15 gtt/mL | General IV fluids (most common) |
| Macro drip | 20 gtt/mL | Standard IV fluids |
| Micro drip | 60 gtt/mL | Pediatric, precise medication delivery |
Watch the drip chamber and count the drops that fall in 15 seconds, then multiply by 4. Adjust the roller clamp until the rate matches your calculated gtt/min.
Use micro drip (60 gtt/mL) for flow rates under 100 mL/hr, pediatric patients, or when precise medication dosing is critical. Use macro drip for higher-volume infusions where exact precision is less critical.
Infusion pumps are programmed in mL/hr, not gtt/min. Use the mL/hr result from this calculator. The pump controls the rate electronically, so the drop factor of the tubing does not matter when using a pump.