10 gtts/mL (Macro Drip)
15 gtts/mL (Macro Drip)
20 gtts/mL (Macro Drip)
60 gtts/mL (Micro Drip)
Check the IV tubing packaging for this value.
Please enter valid positive numbers for Volume and Time.
Flow Rate (mL/hr):0 mL/hr
Drip Rate (drops/min):0 gtts/min
Drops per 15 Seconds:0 drops
Understanding Dosage Rates and IV Calculations
In clinical settings, accurately calculating the dosage rate is critical for patient safety. Whether administering fluids for hydration or delivering precise medication doses, healthcare professionals must ensure the infusion rate matches the physician's orders. This calculator assists in determining two primary metrics: the Flow Rate (how many milliliters per hour) and the Drip Rate (how many drops per minute).
How to Calculate Flow Rate (mL/hr)
The flow rate determines the volume of fluid that enters the patient's body every hour. It is typically programmed into an electronic infusion pump.
Flow Rate (mL/hr) = Total Volume (mL) ÷ Time (hours)
For example, if a doctor orders 1000 mL of Normal Saline to be infused over 8 hours:
1000 mL ÷ 8 hr = 125 mL/hr
How to Calculate Drip Rate (gtts/min)
When an electronic pump is not available, nurses often set the rate manually by counting drops (gtts) in the drip chamber. To calculate this, you need the "Drop Factor" of the tubing being used. Common drop factors include:
Macro Drip: 10, 15, or 20 gtts/mL (used for general hydration or fast rates).
Micro Drip: 60 gtts/mL (used for pediatrics or precise medication delivery).
Using the previous example (1000 mL over 8 hours) with a standard 20 gtts/mL tubing:
Convert hours to minutes: 8 × 60 = 480 minutes.
Multiply volume by drop factor: 1000 × 20 = 20,000.
Divide by total minutes: 20,000 ÷ 480 = 41.6 gtts/min (rounded to 42 drops per minute).
Clinical Safety Tips
Always double-check your calculations. A decimal point error can lead to a 10-fold overdose or underdose. When setting a manual drip rate, it is helpful to divide the minute rate by 4 to see how many drops should fall in 15 seconds, making it easier to count and adjust the roller clamp efficiently.
function calculateDosageRate() {
// 1. Get input values
var volumeInput = document.getElementById("totalVolume");
var timeInput = document.getElementById("infusionTime");
var dropFactorInput = document.getElementById("dropFactor");
var resultsDiv = document.getElementById("resultsDisplay");
var errorDiv = document.getElementById("errorDisplay");
// 2. Parse values
var volume = parseFloat(volumeInput.value);
var time = parseFloat(timeInput.value);
var dropFactor = parseFloat(dropFactorInput.value);
// 3. Validation
if (isNaN(volume) || isNaN(time) || volume <= 0 || time <= 0) {
errorDiv.style.display = "block";
resultsDiv.style.display = "none";
return;
}
// 4. Hide error if valid
errorDiv.style.display = "none";
// 5. Calculate Flow Rate (mL/hr)
// Formula: Volume / Time
var flowRate = volume / time;
// 6. Calculate Drip Rate (gtts/min)
// Formula: (Volume * Drop Factor) / (Time * 60)
var totalMinutes = time * 60;
var dripRate = (volume * dropFactor) / totalMinutes;
// Calculate drops per 15 seconds for easier manual setting
var quarterMinRate = dripRate / 4;
// 7. Display Results
// Rounding logic: Flow rate usually 1 decimal, Drops usually whole number
document.getElementById("flowRateResult").innerHTML = flowRate.toFixed(1) + " mL/hr";
document.getElementById("dripRateResult").innerHTML = Math.round(dripRate) + " gtts/min";
document.getElementById("quarterMinResult").innerHTML = Math.round(quarterMinRate) + " drops";
// Show results container
resultsDiv.style.display = "block";
}