IV Rate Calculator (mL/hr)
Calculate the infusion pump rate based on volume and time.
What is the IV Rate (mL/hr)?
In clinical settings, intravenous (IV) fluids are often administered via an infusion pump. These pumps require the clinician to program a specific flow rate, measured in milliliters per hour (mL/hr). This ensures that the patient receives the correct dosage of medication or hydration over a precise period.
The mL/hr Calculation Formula
The math behind calculating the infusion rate is straightforward. You divide the total volume of fluid by the total time in hours:
Flow Rate (mL/hr) = Total Volume (mL) รท Time (Hours)
If the infusion time includes minutes, you must first convert the minutes into a fraction of an hour by dividing by 60 before adding them to the total hour count.
Step-by-Step Example
Suppose a physician orders 500 mL of Normal Saline to be infused over 4 hours and 30 minutes. Here is how you calculate the rate:
- Convert time to hours: 30 minutes / 60 = 0.5 hours. Total time = 4.5 hours.
- Apply the formula: 500 mL / 4.5 hours = 111.11 mL/hr.
- Final Result: Set the IV pump to 111.1 mL/hr (depending on pump rounding capabilities).
Common IV Rate Reference Table
| Total Volume (mL) | Time Duration | Flow Rate (mL/hr) |
|---|---|---|
| 1000 mL | 8 Hours | 125 mL/hr |
| 1000 mL | 12 Hours | 83.3 mL/hr |
| 500 mL | 4 Hours | 125 mL/hr |
| 250 mL | 1 Hour | 250 mL/hr |
| 100 mL | 30 Minutes | 200 mL/hr |
Why Precision Matters
Calculating the correct mL/hr rate is critical for patient safety. Over-infusion (running the fluid too fast) can lead to fluid overload or medication toxicity, while under-infusion (running the fluid too slow) may result in sub-therapeutic dosing or dehydration. Always double-check calculations and ensure the pump settings match the physician's orders exactly.