Hourly Infusion Rate Calculator

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Hourly Infusion Rate Calculator

10 (Macro) 15 (Macro) 20 (Macro) 60 (Micro)

Results

Hourly Rate: 0 mL/hr

Drip Rate: 0 gtt/min

Note: Rounded to the nearest whole number.

function calculateInfusionRate() { var volume = parseFloat(document.getElementById('volumeInput').value); var hours = parseFloat(document.getElementById('timeHours').value) || 0; var minutes = parseFloat(document.getElementById('timeMinutes').value) || 0; var dropFactor = parseFloat(document.getElementById('dropFactor').value); var totalMinutes = (hours * 60) + minutes; if (isNaN(volume) || totalMinutes <= 0 || isNaN(totalMinutes)) { alert("Please enter a valid volume and time duration."); return; } // Formula: (Volume in mL / Total Minutes) * 60 = mL/hr var mlHr = (volume / totalMinutes) * 60; // Formula: (Volume in mL * Drop Factor) / Total Minutes = gtt/min var gttMin = (volume * dropFactor) / totalMinutes; document.getElementById('resMLHr').innerText = Math.round(mlHr).toLocaleString(); document.getElementById('resGttMin').innerText = Math.round(gttMin).toLocaleString(); document.getElementById('infusionResults').style.display = 'block'; }

Understanding Hourly Infusion Rates

In clinical practice, calculating the correct hourly infusion rate is critical for patient safety and therapeutic efficacy. This calculator helps healthcare professionals determine how many milliliters per hour (mL/hr) a pump should be set to, as well as the manual drip rate (gtt/min) when an infusion pump is unavailable.

The Calculation Formulas

To determine the rates, we use two primary mathematical formulas:

  • Flow Rate (mL/hr): Total Volume (mL) ÷ Total Time (hr)
  • Drip Rate (gtt/min): [Total Volume (mL) × Drop Factor (gtt/mL)] ÷ Total Time (min)

What is a Drop Factor?

The drop factor is the number of drops required to deliver 1 mL of fluid, which is determined by the intravenous (IV) tubing's diameter. Common sizes include:

  • Macro-drip: 10, 15, or 20 gtt/mL (used for routine adult infusions).
  • Micro-drip: 60 gtt/mL (used for pediatric or high-precision medication delivery).

Practical Example

Suppose a physician orders 1,000 mL of Normal Saline to be infused over 8 hours using a 15 gtt/mL administration set.

  1. Convert time to minutes: 8 hours × 60 minutes = 480 minutes.
  2. Calculate mL/hr: 1,000 mL ÷ 8 hours = 125 mL/hr.
  3. Calculate gtt/min: (1,000 mL × 15 gtt/mL) ÷ 480 minutes = 31 gtt/min (rounded).
Disclaimer: This tool is for educational purposes only. Always verify calculations with a second clinician and follow institutional protocols and manufacturer guidelines for medical equipment.

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