Works out how fast an IV infusion should drip — in drops per minute (gtt/min) — from the volume to be infused, the time allowed, and the drop factor printed on the giving set packaging.
Formula: drip rate (gtt/min) = volume (mL) × drop factor (gtt/mL) ÷ time (minutes). Drip rates are rounded to a whole drop — you cannot count part of a drop. This calculator is a study and checking aid: the prescribed rate and your local infusion policy govern practice, and pump infusions should be set in mL/hr.
How do I calculate an IV drip rate?
Multiply the volume to infuse (mL) by the giving set's drop factor (gtt/mL), then divide by the total time in minutes. The result is drops per minute, rounded to a whole number because drops are counted whole. For example, 1,000 mL over 8 hours with a 15 gtt/mL set: 1,000 × 15 ÷ 480 = about 31 gtt/min.
Where do I find the drop factor?
The drop factor is printed on the giving set's packaging. Standard (macro-drip) sets are commonly 10, 15 or 20 drops per millilitre; micro-drip sets are 60 drops per millilitre and are used for slow, precise infusions.
Why is the answer different in mL/hr?
mL/hr is the volume rate — the number a pump is set to — while gtt/min is the drop rate counted at the drip chamber for a gravity infusion. Both describe the same infusion: mL/hr × drop factor ÷ 60 converts between them.