IV Flow Rate Calculator (mL/hr)
Infusion pumps run in mL per hour. Enter the volume and the time to get the pump rate, or the volume and the rate to get how long the infusion takes.
Shows the work. Answer, formula, and numbered steps, rounded the way nursing exams expect. For study and exam practice, not for patient care.
Formula
mL/hr = total volume ÷ total hours.
Fill in the fields and press Calculate to see the answer and every step.
For study and exam practice, not for patient care.
Rounding: Pump rates round to a whole mL/hr unless your pump or program uses tenths. Infusion time rounds to the tenth of an hour.
Worked examples
Infuse 250 mL of 0.45% sodium chloride over 4 hours by infusion pump.
- Solve for
- Pump rate (mL/hr)
- Volume
- 250 mL
- Infusion time
- 4 hours
Formula mL/hr = total volume ÷ total hours.
- mL/hr = total volume ÷ total hours.
- 250 mL ÷ 4 hours = 62.5 mL/hr.
- Round to a whole number: 63 mL/hr.
Answer 63 mL/hr
1,000 mL of 5% dextrose in water is infusing at 150 mL/hr. How long will it take?
- Solve for
- Infusion time (hours)
- Volume
- 1,000 mL
- Rate
- 150 mL/hr
Formula mL/hr = total volume ÷ total hours.
- Hours = volume ÷ rate.
- 1,000 mL ÷ 150 mL/hr = 6.67 hours.
- Round to the nearest tenth: 6.7 hours.
Answer 6.7 hours
FAQ
How do you calculate an IV flow rate in mL/hr?
Divide the total volume in mL by the total time in hours: mL/hr = volume ÷ hours. If the time is in minutes, divide the minutes by 60 first.
How do you find how long an infusion will take?
Divide the volume by the rate: hours = mL ÷ mL/hr.
What is the difference between flow rate and drip rate?
Flow rate is mL/hr, which you program into a pump. Drip rate is drops per minute (gtt/min), which you count for a gravity infusion and depends on the tubing's drop factor.