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IV Drip Rate Calculator

Find the IV pump flow rate (mL/hr) and gravity-set drip rate (gtt/min) from infusion volume, time, and the tubing's drop factor.

Flow rate (pump setting)
125 mL/hr
Drip rate (gravity set)
31.3 gtt/min

How it works

The pump flow rate is just the ordered volume spread evenly over the ordered time: flow rate (mL/hr) = volume (mL) ÷ time (hr). That's what you'd dial into an infusion pump.

For a gravity-fed set with no pump, that hourly rate has to be translated into a countable drip rate using the drop factor printed on the IV tubing packaging — how many drops make up 1 mL for that specific tubing set: drip rate (gtt/min) = flow rate (mL/hr) × drop factor (gtt/mL) ÷ 60. Macrodrip sets are commonly 10, 15, or 20 gtt/mL; microdrip (often pediatric) sets are 60 gtt/mL.

A 60 gtt/mL set has a handy side effect: because it also divides by 60, the drip rate in gtt/min comes out numerically identical to the flow rate in mL/hr — a shortcut many nursing programs teach explicitly.

FAQ

Where do I find the drop factor for my tubing?

It's printed directly on the IV administration set's packaging, usually stated as "gtt/mL" — it's a property of that specific tubing set, not something to estimate or look up elsewhere.

Why does a 60 gtt/mL set make the drip rate equal the flow rate?

Drip rate = (flow rate × drop factor) ÷ 60. When the drop factor is exactly 60, that division cancels the multiplication, leaving drip rate = flow rate numerically (the units are still different — mL/hr versus gtt/min — but the number is the same).

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