About

When electronic infusion pumps are unavailable or contraindicated, nurses must rely on gravity-fed IV lines regulated by a manual roller clamp. To deliver a precise volume over a set time, the flow must be counted in "drops per minute" (gtt/min). This calculation depends entirely on the tubing calibration, known as the "Drop Factor" (drops per milliliter).

This tool solves the equation and provides a crucial visual aid: a Metronome. Once calculated, the tool blinks at the exact rhythm required. The nurse can watch the physical drip chamber and adjust the roller clamp until the falling drops synchronize with the visual indicator on the screen, ensuring accurate dosing.

Formulas

The flow rate in drops per minute is derived from the total volume, the tubing calibration, and the duration in minutes.

Rate (gtt/min) = Volume (mL) × Drop Factor (gtt/mL)Time (min)

Reference Data

Tubing Type	Drop Factor	Use Case	Drop Size
Macrodrip (Standard)	10 gtt/mL	Trauma, Rapid fluid resuscitation, Blood products.	Large
Macrodrip (Common)	15 gtt/mL	Standard hydration, Antibiotics.	Medium
Macrodrip (Surgical)	20 gtt/mL	Routine maintenance fluids.	Medium-Small
Microdrip (Pediatric)	60 gtt/mL	Pediatrics, Neonates, Potent medications (if no pump).	Tiny (60 gtt = 1 mL)

Frequently Asked Questions

Macrodrip tubing delivers large drops (10-20 drops = 1 mL) and is used for fast infusions ( > 100 mL/hr). Microdrip tubing delivers tiny drops (60 drops = 1 mL) and is used for slow, precise infusions or pediatric patients.

The Drop Factor is printed prominently on the packaging of the IV tubing set (e.g., '15 Drops/mL'). It is a physical property of the plastic spike and drip chamber.

After calculating, press the "Start Metronome" button. A circle will flash at the calculated rate. Hold your phone near the IV drip chamber and adjust the roller clamp until the physical drop falls exactly when the light flashes.

Gravity drips are inherently less precise than pumps due to limb position and bag height changes. While this calculator provides the correct initial rate, frequent re-checks are mandatory.