IV Drip Rate Calculator

The IV Drip Rate Calculator (also IV flow rate calculator), assists in calculating the exact drip rate for intravenous fluids. It is based on the prescribed volume and duration for administering the medication to the patient.

Drip Rate Calculator / IV Flow Rate Calculation

IV Drip Rate Calculator

IV Drip Rate Calculator

What is the IV drip Rate / flow rate?

The IV flow rate, often expressed in milliliters per hour (mL/hr), is the rate at which an intravenous (IV) fluid or medication should be administered to a patient through an IV infusion. It indicates how quickly the fluid or medication should be delivered into the patient's bloodstream to achieve the desired therapeutic effect.

The IV flow rate is determined based on several factors, including the prescribed volume of the fluid or medication, the duration over which it should be administered, and the type of IV infusion set being used.

IV Drip Rate Calculation Formula

The formula to calculate the IV drip rate (in drops per minute, or gtts/min) is as follows:

Drip Rate(gtts/min)= 
( Volume(mL) × DropFactor ) / ( Time in(h) * 60 )


  1. Volume (mL): is the total volume of the intravenous fluid or medication to be administered.
  2. Time (min): is the total time over which the fluid or medication should be infused.
  3. Drop Factor: The number of drops (gtt) in 1 mL of the IV solution depends on the type of IV tubing in use.
  4. Common drop factors include 10, 15, and 20 gtts/mL.

How do you calculate IV drip rate? example

To calculate the IV drip rate, you'll need the following information:

  1. Volume (mL);
  2. Time (min);
  3. Drop Factor;

Here's an example of how to calculate the IV drip rate:

Suppose your prescription is to administer 500 mL of medication over a period of 2 hours (120 minutes), and the IV tubing has a drop factor of 15 gtts/mL.

Using the Drip Rate formula:

Drip Rate (gtts/min)= ( Volume(mL) × DropFactor ) / ( Time in(h) * 60 )

  1. Volume (mL) = 500 mL
  2. Time (min) = 120 min
  3. Drop Factor = 15 gtts/mL

Now, plug these values into the formula:

Calculating IV flow rate

Drip Rate (gtts/min)= ( 500 mL × 15 gtts/mL ) / ( 120 min ) = 62.5 gtts/min

So, in this example, the IV drip rate would be 62.5 drops per minute. To ensure the correct administration over the 2-hour period, you should set the IV infusion device to deliver the medication at this rate.

How long does a 1000 mL saline drip take?

The time it takes to administer a 1000 mL saline drip depends on the prescribed IV drip rate. To calculate the duration, you'll need to know the drip rate in drops per minute (gtts/min) or milliliters per hour (mL/hr).

How many drops per minute is 100 mL per hour?

To calculate the number of drops per minute for a given infusion rate of 100 mL per hour, you must know the drop factor, which the manufacturer typically provides for the specific IV tubing in use. The drop factor tells you how many drops are in 1 mL of the IV solution.

Let's assume a common drop factor of 20 gtts/mL:

Now, to calculate the drops per minute for 100 mL per hour, you can use the following formula:

Drops per Minute (gtts/min) = (Infusion Rate (mL/hr) / 60) × Drop Factor

So, drops per Minute (gtts/min) = (100 mL/hr / 60) × 20 gtts/mL

Finally, Drops per Minute (gtts/min) = (100 / 60) × 20 = 33.33 gtts/min

So, at an infusion rate of 100 mL per hour with a drop factor of 20 gtts/mL, the IV will deliver approximately 33.33 drops per minute. You can round this to the nearest whole number, which would be 33 drops per minute.

How do you calculate flow rate?

To calculate the flow rate of a liquid, you need to know two key pieces of information:

  1. Volume: The total volume of liquid that needs to be delivered.
  2. Time: The duration over which you want to deliver that volume.

The formula for calculating the flow rate (in volume per unit of time) is:

Flow Rate = Volume / Time

Flow Rate is typically expressed in units like liters per minute (L/min) or milliliters per hour (mL/hr), depending on the specific context.

Here are a couple of examples for calculating flow rate:

Example 1 - Flow Rate in Liters per Minute (L/min):

Suppose you need to deliver 1 liter of water over the course of 30 minutes. To calculate the flow rate:

Next, Flow Rate (L/min) = Volume(L)​ / Time(min)

Flow Rate (L/min) = 1L / 30 min =0.03 L/min, so the flow rate is 0.03 liters per minute.

Example 2 - Flow Rate in Milliliters per Hour (mL/hr):

Let's say you have to administer 600 mL of medication over 2 hours. To calculate the flow rate:

Next, Flow Rate (mL/hr) = Volume(mL)​ / Time(hr)

So,the Flow Rate (mL/hr) = 600ml / 2h = 300mL/hr. So the flow rate in this case is 300 milliliters per hour.

IV Flow Rate Calculation Exercise

Example 1:

A patient requires the administration of 500 mL of saline solution over a period of 4 hours. Let's calculate the rate in mL/hour:

Rate (mL/hour) = 500 mL / 4 hours = 125 mL/hour

Example 2:

For a given medication solution, the drop factor is 20 drops/mL. If 300 mL of this solution needs to be administered in 1 hour, let's calculate the rate in drops/minute:

Rate (drops/min) = 300 mL x 20 drops/mL / 60 minutes = 100 drops/min

Example 3: Calculating Saline Solution IV Flow Rate

A patient needs to receive 1000 mL of saline solution over an 8-hour period. To calculate the rate in mL/hour, we use the formula:

Rate (mL/hour) = Volume (mL) / Time (hours)

Rate (mL/hour) = 1000 mL / 8 hours = 125 mL/hour

Example 4: Calculating Amoxicillin IV Drip Rate

Amoxicillin Infusion Rate Calculation A pediatrician prescribes an amoxicillin infusion for a child with a bacterial infection. The doctor prescribes a dose of 500 mg of amoxicillin to be administered over 30 minutes. The amoxicillin vial indicates that each mL contains 50 mg of amoxicillin. Let's calculate the infusion rate in mL/minute required to administer the prescribed dose.

  1. Calculation of the total volume needed: Dose (mg) = 500 mg Concentration (mg/mL) = 50 mg/mL

Total volume (mL) = Dose (mg) / Concentration (mg/mL) = 500 mg / 50 mg/mL = 10 mL

  1. Calculation of the rate in mL/minute: Time (minutes) = 30 minutes

Rate (mL/minute) = Total volume (mL) / Time (minutes) = 10 mL / 30 minutes ≈ 0.33 mL/minute

The amoxicillin infusion rate to administer 500 mg over a 30-minute period would be approximately 0.33 mL/minute when using an amoxicillin vial with a concentration of 50 mg/mL.


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