IV Infusion Rate Calculator

Convert a prescribed infusion dose into a pump rate in mL/hour using the bag concentration and, where dosing is weight-based, the patient's weight. Pure unit arithmetic on an order that has already been written.

💧 Dosing Arithmetic📐 Rate (mL/hr) = dose × weight × 60 / concentration🏥 Health
Dose units
Ordered dose
Patient weight (kg)
Drug amount in bag (mg)
Bag volume (mL)
Please enter valid values.

Formula & Reference

VariableSymbolFormulaUnits
IV Infusion Rate CalculatorRate (mL/hr) = dose × weight × 60 / concentrationmL/hour

Step-by-Step Examples

Example 1
Weight-Based Infusion

Order: 5 mcg/kg/min. Patient 70 kg. Bag: 400 mg in 250 mL.

  • Dose per hour = 5 × 70 × 60 = 21,000 mcg/hr = 21 mg/hr
  • Concentration = 400 / 250 = 1.6 mg/mL
  • Rate = 21 / 1.6 = 13.1 mL/hr
✓ 13.1 mL/hr
Example 2
Fixed Hourly Dose

Order: 8 mg/hr. Bag: 250 mg in 500 mL.

  • Concentration = 250 / 500 = 0.5 mg/mL
  • Rate = 8 / 0.5 = 16 mL/hr
✓ 16 mL/hr
Example 3
Microgram-per-Minute Order

Order: 10 mcg/min. Bag: 4 mg in 250 mL.

  • Dose per hour = 10 × 60 = 600 mcg/hr = 0.6 mg/hr
  • Concentration = 4 / 250 = 0.016 mg/mL
  • Rate = 0.6 / 0.016 = 37.5 mL/hr
✓ 37.5 mL/hr

Real-World Applications

Common Mistakes to Avoid

⚠️
Mixing microgram and milligram units

The most common source of error is a thousand-fold mistake between mcg and mg. Confirm the units on both the order and the bag label before calculating.

⚠️
Assuming a standard bag concentration

Concentrations vary between institutions and between double-strength or fluid-restricted preparations. Always read the actual label rather than recalling a usual value.

⚠️
Using this as the sole check

This tool performs arithmetic on numbers you enter. It cannot verify that the order itself is appropriate, that the drug is correct, or that the patient can tolerate it.

Frequently Asked Questions

How do I calculate an IV infusion rate?
Convert the ordered dose into milligrams per hour, calculate the bag concentration in milligrams per millilitre, then divide the hourly dose by the concentration.
What is the difference between mcg/kg/min and mg/hr orders?
Weight-based orders scale with the patient and are typical for vasoactive drugs; fixed hourly orders do not, and are common for infusions where weight matters less.
Why does the calculation multiply by 60?
To convert a per-minute dose into a per-hour dose, since infusion pumps are programmed in millilitres per hour.
Does this tool decide what dose to give?
No. It converts a dose that a prescriber has already ordered into a pump rate. It has no opinion on whether the dose is correct.
Should I rely on this instead of my institution's protocol?
No. Institutional protocols, smart pump libraries, and required double-checks exist precisely because infusion errors are high-consequence. Use this as a cross-check only.

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