How this calculator works
Use the drop factor printed on the actual administration set. Volume and time are converted before applying the gravity-infusion equation. A separate result shows rounding to a whole drop; that rounding changes the delivered rate and requires clinical checking. The pump mode converts an entered mL/h rate without needing a bag volume. The result is an estimate for information only and is not medical advice.
Formula
Drops/min = volume (mL) × drop factor (drops/mL) / time (min). mL/h = volume / hours. Pump conversion: drops/min = mL/h × drops/mL / 60.
Worked example
1000 mL over 8 hours through 20 drops/mL tubing gives 41.6667 drops/min and 125 mL/h. 500 mL over 4 hours through 60 drops/mL tubing gives 125 drops/min.
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Frequently asked questions
Can a drop factor be inferred?
Yes, algebraically. Confirm the result against the tubing label rather than using an inferred value for an unknown set.
Are drops always the same volume?
No. The labelled drop factor depends on the administration set; use the correct set and manufacturer instructions.
Why display both exact and whole drops?
The exact number exposes the arithmetic. A gravity set is counted in discrete drops, so whole-drop rounding affects the actual rate.