Nursing

IV Flow Rate Calculator (mL/hr)

The IV flow rate calculator determines the rate in millilitres per hour (mL/hr) to program into an infusion pump, given the total volume to be infused and the prescribed duration. This is the most common IV calculation nurses perform when setting up electronic infusion devices. The result should be entered directly into the pump — always verify the programmed rate against the physician's order before starting.

Infusion Pump Rate

Formula

Rate (mL/hr) = Volume (mL) ÷ Time (hours)
📖 Formula source: INS Standards of Practice for Infusion Therapy, 2021.

Related Calculators

Frequently Asked Questions

How do I calculate mL/hr for an IV infusion?

Divide the total volume in mL by the infusion time in hours. For example, 500 mL over 4 hours = 500 ÷ 4 = 125 mL/hr. Program this rate into the infusion pump.

Can I use this for blood transfusions?

Yes. For blood products, divide the total volume by the prescribed infusion time. A standard unit of packed red blood cells (approx 300 mL) over 2 hours = 150 mL/hr. Always follow your institution's transfusion protocol and monitor the patient closely.

Set the infusion pump to the calculated rate. Always verify the pump setting against the physician's order before starting infusion.