Calculate fluid requirements using the Holiday-Segar (4-2-1) Rule
Calculation Results
Hourly Maintenance Rate:0 mL/hr
Daily Maintenance Volume:0 mL/day
Understanding IV Drip Maintenance Rates
In clinical practice, determining the correct intravenous (IV) maintenance fluid rate is critical for patients who are unable to maintain adequate hydration through oral intake. The most widely accepted standard for this calculation is the Holiday-Segar Rule, often referred to as the 4-2-1 Rule.
The 4-2-1 Rule Formula
This method calculates the hourly fluid requirement (mL/hr) based on the patient's body weight in kilograms. It is broken down into three tiers:
First 10 kg: 4 mL/kg/hr
Next 10 kg (11-20 kg): 2 mL/kg/hr
Every kg above 20 kg: 1 mL/kg/hr
Calculation Examples
Patient Weight
Calculation Logic
Resulting Rate
8 kg
8 kg × 4 mL/hr
32 mL/hr
15 kg
(10 kg × 4) + (5 kg × 2)
50 mL/hr
70 kg
(10 kg × 4) + (10 kg × 2) + (50 kg × 1)
110 mL/hr
Clinical Significance
Maintenance fluids are intended to replace "insensible losses" (from skin and lungs) and provide enough water for the kidneys to excrete metabolic waste. While the 4-2-1 rule is the standard for healthy pediatric and adult populations, clinicians must adjust rates for specific conditions such as:
Renal Failure: Fluids must be restricted to prevent overload.
Heart Failure: Requires careful monitoring to avoid pulmonary edema.
Dehydration: Maintenance rates do not include "bolus" volumes needed to correct existing fluid deficits.
SIADH: May require significant fluid restriction.
Daily Fluid Requirements (100/50/20 Rule)
If you prefer to calculate the total volume for a 24-hour period directly, the 100/50/20 rule is used:
100 mL/kg for the first 10 kg
50 mL/kg for the next 10 kg
20 mL/kg for each kg thereafter
This calculator automatically provides both the hourly rate and the total 24-hour volume to assist in clinical decision-making and pump programming.
function calculateIVRate() {
var weight = parseFloat(document.getElementById('patientWeight').value);
var hourlyRate = 0;
var resultDiv = document.getElementById('ivResult');
var hourlyRes = document.getElementById('hourlyRes');
var dailyRes = document.getElementById('dailyRes');
if (isNaN(weight) || weight <= 0) {
alert("Please enter a valid patient weight greater than 0.");
resultDiv.style.display = "none";
return;
}
// Applying the 4-2-1 Rule
if (weight <= 10) {
hourlyRate = weight * 4;
} else if (weight <= 20) {
hourlyRate = 40 + ((weight – 10) * 2);
} else {
hourlyRate = 60 + ((weight – 20) * 1);
}
var dailyTotal = hourlyRate * 24;
// Update Display
hourlyRes.innerHTML = hourlyRate.toFixed(1) + " mL/hr";
dailyRes.innerHTML = dailyTotal.toFixed(1) + " mL/day";
resultDiv.style.display = "block";
}