IV Drip Rate Calculator

Variables and formula

In order to ensure that the intravenous fluid infusion is administered at the right rate, the amount of fluid and the administration time are required during prescription and the calculation then accounts for the type of drip set used.

The three variables are:

■ Volume to be given in mL;

■ Time expressed in minutes or hours;

■ Drop factor (macrodrip tubing) in gtts/mL.

The equation behind the IV drip rate calculator is:

IV Drip rate = (Volume to be given in mL x Drop factor in gtts/min) / Time in minutes

In case the time is expressed in hours then the flow rate calculation becomes:

IV Drip rate = (Volume to be given in mL x Drop factor in gtts/min) / (Time in hours x 60)

How to calculate IV drip rate

Taking the case of a simple infusion of 1,000 mL of 0.9% sodium chloride over 8 hours, administered through a macrodrip tubing with a drop factor of 15 gtts/mL, the calculation would be:

IV Drip rate = (1000 mL x 15 gtts/mL) / (8 hours x 60) = 31.25 gtts per minute.

About drip sets

Intravenous administration is the fastest way to deliver the following to the body:

■ Fluids for correcting dehydration;

■ Fluids for correcting electrolyte imbalance;

■ Fluid infusion with medication;

■ Blood transfusion.

The rate at which a fluid is administered intravenously is measured in mL/hour or drops per minute.

The regulation of IV flow rate is done by a burette, which contains a needle or a plastic dropper. The most common drip sets are:

■ 60 gtts/ml minidrip drip set;

■ 10 gtts/ml regular drip set;

■ 15 gtts/ml regular drip set;

■ 20 gtts/ml regular drip set.

References

1. Duell, D. J., Martin, B. C., & Smith, S. F. Clinical nursing skills: Basic to advanced skills (6th edition). 2004. Upper Saddle River, NJ: Pearson Education.

2. Pugsley HE, Farquharson RF. Factors Influencing the Rate of Flow of Intravenous Infusions. Can Med Assoc J. 1944; 51(1): 5–11.