Please enter a valid volume and time duration greater than zero.
Required Flow Rate
0mL/hr
Understanding the IV Infusion Rate Formula
In clinical settings, accurately calculating the intravenous (IV) infusion rate is a critical skill for nurses and medical professionals. The infusion rate determines how much fluid or medication a patient receives over a specific period. This calculator uses the standard volumetric flow rate formula to determine how many milliliters (mL) should be infused per hour.
The mL/hr Formula
To calculate the IV flow rate in mL/hr manually, you need two key pieces of information: the total volume of fluid to be infused and the total time duration for the infusion.
Rate (mL/hr) = Total Volume (mL) ÷ Total Time (hours)
If the time is provided in minutes, convert it to hours first by dividing the minutes by 60.
Step-by-Step Calculation Example
Let's look at a realistic scenario often found in nursing practice or NCLEX questions:
Prescription: Infuse 1,000 mL of 0.9% Normal Saline (NS) over 8 hours.
Step 1: Identify the Total Volume = 1,000 mL.
Step 2: Identify the Total Time = 8 hours.
Step 3: Apply the formula: 1,000 ÷ 8.
Result: 125 mL/hr.
This means you would set the IV pump to deliver fluid at a rate of 125 milliliters per hour.
Handling Minutes
Sometimes an order might read: "Infuse 100 mL of Antibiotic over 30 minutes."
Step 2: Divide Volume by Hours: 100 mL ÷ 0.5 hours.
Result: 200 mL/hr.
Why Accuracy Matters
Incorrect infusion rates can lead to serious complications. A rate that is too slow may result in inadequate therapeutic levels of a drug or dehydration. Conversely, a rate that is too fast can cause fluid overload, heart failure, or toxicity. Always double-check your calculations and verify pump settings against the physician's order.
When to Use This Calculator
This tool is designed for calculating the volumetric rate for electronic infusion pumps (EID). If you are calculating gravity drip rates (using a manual roller clamp), you would need to calculate drops per minute (gtt/min), which requires the drop factor of the tubing (e.g., 10, 15, 20, or 60 gtt/mL).
function calculateFlowRate() {
// 1. Get Input Elements by ID exactly as defined in HTML
var volumeInput = document.getElementById('ivTotalVolume');
var hoursInput = document.getElementById('ivHours');
var minutesInput = document.getElementById('ivMinutes');
var resultBox = document.getElementById('ivResult');
var rateValueSpan = document.getElementById('rateValue');
var errorMsg = document.getElementById('ivErrorMessage');
// 2. Parse values (Handle empty strings as 0)
var volume = parseFloat(volumeInput.value);
var hours = parseFloat(hoursInput.value);
var minutes = parseFloat(minutesInput.value);
// Treat empty inputs as 0 for logic, but we need to validate total time > 0
if (isNaN(hours)) hours = 0;
if (isNaN(minutes)) minutes = 0;
// 3. Validation Logic
// Check if volume is a valid number and > 0
if (isNaN(volume) || volume 0
var totalHours = hours + (minutes / 60);
if (totalHours <= 0) {
errorMsg.style.display = 'block';
errorMsg.innerText = "Total duration must be greater than zero.";
resultBox.style.display = 'none';
return;
}
// 4. Calculate Rate (mL / hr)
var flowRate = volume / totalHours;
// 5. Rounding Logic
// IV pumps usually allow 1 decimal place, sometimes whole numbers only.
// We will round to 1 decimal place for precision.
var displayRate = Math.round(flowRate * 10) / 10;
// 6. Display Result
errorMsg.style.display = 'none';
rateValueSpan.innerText = displayRate;
resultBox.style.display = 'block';
}