Estimate fuel costs and quantity for your next road trip
Imperial (Miles / MPG)
Metric (KM / L/100km)
Total Fuel Required:0
Total Estimated Cost:$0.00
Cost Per Person:$0.00
How to Calculate Trip Gas Costs
Planning a road trip requires more than just a map; you need a budget. Fuel is often the largest variable expense. This gas calculator helps you determine exactly how much you'll spend at the pump by analyzing your vehicle's efficiency against the distance of your journey.
The Mathematics of the Trip
The calculation differs slightly based on the units you use:
Imperial System: If you use Miles and MPG (Miles Per Gallon), the formula is: (Distance / MPG) × Price per Gallon.
Metric System: If you use Kilometers and L/100km, the formula is: (Distance / 100) × Fuel Consumption × Price per Liter.
Example Calculation
Suppose you are driving from Los Angeles to San Francisco, a distance of approximately 380 miles. Your car gets 30 MPG, and the current gas price is $4.50 per gallon. You are traveling with 3 friends (4 people total).
Fuel Needed: 380 / 30 = 12.67 Gallons
Total Cost: 12.67 × $4.50 = $57.01
Split Cost: $57.01 / 4 = $14.25 per person
Tips for Reducing Gas Consumption
To maximize your efficiency and lower the costs calculated above, consider these strategies:
Check Tire Pressure: Under-inflated tires increase rolling resistance and reduce fuel economy.
Limit Excessive Idling: If you're stopped for more than a minute, it's usually more efficient to turn off the engine.
Use Cruise Control: Maintaining a steady speed on highways prevents the fuel-heavy fluctuations of frequent braking and acceleration.
Lighten the Load: Every extra 100 pounds in your trunk can reduce your MPG by about 1%.
function calculateTripGas() {
var distance = parseFloat(document.getElementById('tripDistance').value);
var efficiency = parseFloat(document.getElementById('fuelEfficiency').value);
var price = parseFloat(document.getElementById('gasPrice').value);
var passengers = parseInt(document.getElementById('passengers').value);
var unit = document.getElementById('unitType').value;
if (isNaN(distance) || isNaN(efficiency) || isNaN(price) || distance <= 0 || efficiency <= 0 || price <= 0) {
alert("Please enter valid positive numbers for distance, efficiency, and price.");
return;
}
if (isNaN(passengers) || passengers < 1) {
passengers = 1;
}
var totalFuel = 0;
var totalCost = 0;
var unitLabel = "";
var fuelLabel = "";
if (unit === "imperial") {
// Miles and MPG
totalFuel = distance / efficiency;
unitLabel = " Gallons";
} else {
// KM and L/100km
totalFuel = (distance / 100) * efficiency;
unitLabel = " Liters";
}
totalCost = totalFuel * price;
var perPerson = totalCost / passengers;
document.getElementById('resFuelNeeded').innerHTML = totalFuel.toFixed(2) + unitLabel;
document.getElementById('resTotalCost').innerHTML = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resCostPerPerson').innerHTML = "$" + perPerson.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('tripResults').style.display = "block";
}