Fuel Cost Calculator — What Will Gas Cost for Your Trip?
You know the distance and roughly what your car drinks. The missing piece is what the trip costs, and what each passenger owes. Put in distance, fuel economy, and fuel price, and you get fuel used, total cost, cost per mile, and each person’s share.
Enter your numbers
Result
Three numbers, one answer
Fuel cost comes from three numbers: how far you drive, how thirsty your car is, and what fuel costs. In imperial units, Gallons used = Distance ÷ MPG. Fuel cost = Gallons used × Price per gallon. Cost per mile = Fuel cost ÷ Distance. In metric, Litres used = Distance (km) × L/100 km ÷ 100, then Fuel cost = Litres used × Price per litre.
Distance comes from your maps app, or the road signs on the route. MPG comes from your dashboard readout, or the car’s official rating. Fuel price comes from the station you plan to use, since prices vary by area. Set the Round trip dropdown to Yes if you are coming back the same way, which doubles the distance and is the usual case for a day out. Split the cost between passengers if you are sharing the ride.
A weekend trip, priced
A weekend trip: 320 miles one way, car rated at 28 MPG, fuel at $3.60 per gallon, round trip, split between 4 people. One-way fuel is 320 ÷ 28 = 11.43 gallons. One-way cost is 11.43 × $3.60 = $41.14. Round trip doubles it: $41.14 × 2 = $82.29, which is 22.86 gallons over 640 miles. Cost per mile is $82.29 ÷ 640 = $0.13 per mile. Each person’s share is $82.29 ÷ 4 = $20.57 each.
The per-mile figure is the most useful number for comparing trips. At $0.13 a mile, a 50-mile detour costs about $6.50 in fuel.
Why the real bill runs higher
Real MPG is usually lower than the official rating. A full car, hills, a roof box, and air conditioning all push fuel use up, so add 10–15% as a safety margin on long trips. Fuel prices change by station and by day, so use the price where you will actually fill up. Traffic and detours add miles, so round the distance up slightly if your route is uncertain.
And this calculator covers fuel only, not tolls, parking, food, or wear on the car. If you are budgeting a whole trip, those go on top.
The shortcuts people use most are round trip or one way, MPG units, splitting between 2–6 passengers, and a quick estimate with 10% extra for real-world driving.
Questions
How do I calculate fuel cost for a trip?
Divide the trip distance by your car’s MPG to get gallons used, then multiply by the fuel price. For a round trip, double the distance first. The calculator above does all of it for you.
What is a good MPG to use in the calculator?
Use your car’s real average from the dashboard if you have it. It reflects your driving. The official rating is a fair fallback, but expect real-world MPG to run a little lower.
Does the calculator include the return journey?
Yes. Set the Round trip dropdown to Yes and the distance, fuel, and cost all double. Leave it set to No for a one-way trip.
Why is my real fuel bill higher than the estimate?
The usual causes are lower real MPG (load, hills, AC, city traffic), a higher pump price than the one entered, and extra miles from detours or traffic. Add a 10–15% margin when budgeting.
If this wasn’t the one
If you need the drive time rather than the cost, the Time Duration Calculator works out how long the drive takes, including stops. The Speed Calculator gives average speed and pace for distance and time. The Tip Calculator splits the meal bill at the roadside stop. And the Loan Calculator works out monthly payments if you are financing a car. How to Calculate Fuel Cost for a Trip covers the full method with examples. All Everyday Calculators · All Calculators