Nursing Dosage and IV Rate Calculator

Accurate medication dosage calculation is a cornerstone of safe nursing practice. Errors in dosage can lead to serious patient harm. This calculator is designed to assist nurses, nursing students, and healthcare professionals in quickly and accurately determining medication dosages and intravenous (IV) infusion rates. Always double-check your calculations with another qualified professional before administering medication.

Understanding Dosage Calculations

Medication dosage calculations typically involve determining how much medication to administer based on a desired dose and the concentration of the medication available. The fundamental formula often used is:

(Desired Dose / Medication On Hand) × Volume/Tablets On Hand = Amount to Administer

For IV infusions, calculating the correct rate ensures the medication is delivered over the prescribed time. This can be expressed in milliliters per hour (mL/hr) or drops per minute (gtts/min).

mL/hr: Total Volume (mL) / Infusion Time (hours) = mL/hr
gtts/min: (Total Volume (mL) × Drop Factor (gtts/mL)) / Infusion Time (minutes) = gtts/min

The drop factor is specific to the IV tubing set being used (e.g., 10 gtts/mL, 15 gtts/mL, 20 gtts/mL, 60 gtts/mL for microdrip).

How to Use This Calculator

Enter the required values into the appropriate fields below. The calculator will provide the calculated dosage or infusion rate. Ensure all units are consistent (e.g., if desired dose is in mg, medication on hand should also be in mg).

Medication Dosage Calculator

Use this section to calculate the amount of medication to administer based on desired dose and available concentration.

Desired Dose (e.g., mg, mcg, units):

Medication On Hand (e.g., mg, mcg, units):

Volume/Tablets On Hand (e.g., mL, tablets):

IV Infusion Rate Calculator

Use this section to calculate IV infusion rates in mL/hr and gtts/min.

Total Volume to Infuse (mL):

Infusion Time (hours):

Drop Factor (gtts/mL, optional for mL/hr):

Examples of Dosage Calculations

Example 1: Oral Medication

A physician orders 0.25 mg of Digoxin. The pharmacy supplies Digoxin tablets labeled 0.125 mg per tablet. How many tablets should the nurse administer?

Desired Dose: 0.25 mg
Medication On Hand: 0.125 mg
Volume/Tablets On Hand: 1 tablet
Calculation: (0.25 mg / 0.125 mg) × 1 tablet = 2 tablets

Result: Administer 2 tablets.

Example 2: Liquid Medication

The order is for Amoxicillin 250 mg orally. The medication available is Amoxicillin 125 mg/5 mL. How many mL should the nurse administer?

Desired Dose: 250 mg
Medication On Hand: 125 mg
Volume/Tablets On Hand: 5 mL
Calculation: (250 mg / 125 mg) × 5 mL = 10 mL

Result: Administer 10 mL.

Example 3: IV Infusion Rate (mL/hr)

An order is for 1000 mL of 0.9% Normal Saline to infuse over 8 hours. What is the infusion rate in mL/hr?

Total Volume to Infuse: 1000 mL
Infusion Time: 8 hours
Calculation: 1000 mL / 8 hours = 125 mL/hr

Result: Infuse at 125 mL/hr.

Example 4: IV Infusion Rate (gtts/min)

Using the same order as Example 3 (1000 mL over 8 hours), and the IV tubing has a drop factor of 15 gtts/mL. What is the drip rate in gtts/min?

Total Volume to Infuse: 1000 mL
Infusion Time: 8 hours (convert to minutes: 8 × 60 = 480 minutes)
Drop Factor: 15 gtts/mL
Calculation: (1000 mL × 15 gtts/mL) / 480 minutes = 15000 / 480 = 31.25 gtts/min

Result: Infuse at approximately 31 gtts/min (round to nearest whole number for drops).

Nursing Dosage Calculations