Compare two vehicles to see how much you can save on gas.
Your Estimated Savings:
Monthly Fuel Saved:0 Gallons
Monthly Cost Savings:$0.00
Annual Fuel Saved:0 Gallons
Annual Cost Savings:$0.00
5-Year Savings:$0.00
How Fuel Savings are Calculated
Deciding between a standard internal combustion engine and a high-efficiency hybrid or electric vehicle often comes down to the "payback period." Our Fuel Savings Calculator uses a straightforward physical formula to determine the difference in consumption between two vehicles based on their Miles Per Gallon (MPG) ratings.
The math follows this logic: (Distance / Vehicle A MPG) – (Distance / Vehicle B MPG) = Fuel Saved. We then multiply that volume by the current price of fuel to find your monetary benefit.
Example Calculation
Imagine you drive 15,000 miles per year. Your current SUV gets 18 MPG, and you are considering a hybrid that gets 45 MPG. With gas at $3.80 per gallon:
Vehicle A: 15,000 / 18 = 833.33 gallons per year.
Vehicle B: 15,000 / 45 = 333.33 gallons per year.
Difference: 500 gallons saved.
Total Savings: 500 x $3.80 = $1,900 per year.
Why Efficiency Matters More at Low MPG
One common misconception is that the jump from 40 to 50 MPG is as valuable as the jump from 10 to 20 MPG. In reality, improving efficiency on a gas-guzzler provides much higher financial returns. This is known as the "MPG Illusion." Moving from a 15 MPG vehicle to a 20 MPG vehicle saves significantly more fuel over the same distance than moving from a 40 MPG car to a 50 MPG car.
Factors That Influence Your Results
While this calculator provides a highly accurate mathematical estimate, real-world conditions may vary your actual savings:
Driving Habits: Aggressive acceleration and heavy braking can reduce efficiency by up to 30%.
Terrain: Hilly environments require more energy than flat highways.
Climate: Cold weather and air conditioning usage both impact fuel economy.
Maintenance: Under-inflated tires and dirty air filters increase fuel consumption.
function calculateFuelSavings() {
var distance = parseFloat(document.getElementById("distance").value);
var gasPrice = parseFloat(document.getElementById("gasPrice").value);
var mpgA = parseFloat(document.getElementById("mpgA").value);
var mpgB = parseFloat(document.getElementById("mpgB").value);
var resultDiv = document.getElementById("fuelResult");
if (isNaN(distance) || isNaN(gasPrice) || isNaN(mpgA) || isNaN(mpgB) || mpgA <= 0 || mpgB <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Calculations
var fuelUsedA = distance / mpgA;
var fuelUsedB = distance / mpgB;
var monthlyFuelSaved = fuelUsedA – fuelUsedB;
var monthlyCashSaved = monthlyFuelSaved * gasPrice;
var annualFuelSaved = monthlyFuelSaved * 12;
var annualCashSaved = monthlyCashSaved * 12;
var fiveYearSaved = annualCashSaved * 5;
// Display Results
document.getElementById("monthlyFuelSaved").innerHTML = monthlyFuelSaved.toFixed(2) + " Gallons";
document.getElementById("monthlyCashSaved").innerHTML = "$" + monthlyCashSaved.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("annualFuelSaved").innerHTML = annualFuelSaved.toFixed(2) + " Gallons";
document.getElementById("annualCashSaved").innerHTML = "$" + annualCashSaved.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("fiveYearSaved").innerHTML = "$" + fiveYearSaved.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
resultDiv.style.display = "block";
// Smooth scroll to results on mobile
if (window.innerWidth < 600) {
resultDiv.scrollIntoView({ behavior: 'smooth' });
}
}