Calculate fuel efficiency, consumption, economy & trip cost
The Fuel Cost Calculator works out what a drive actually costs, whether you're planning a road trip, comparing two vehicles, or just trying to figure out where your gas money is going each month. Instead of guessing or doing the math by hand, you plug in distance, fuel price, and your vehicle's fuel efficiency, and it returns the total cost along with the underlying mileage figures. It's built for anyone who wants a quick, reliable number before they fill up or hit the road — commuters budgeting for gas, drivers pricing out a long-distance trip, or people shopping for a more fuel-efficient car.
The calculator has four tabs. Fuel Efficiency takes the distance you drove and the fuel you used (miles or kilometers, gallons or liters) and returns your real-world efficiency, the total fuel cost, cost per mile or kilometer, and the CO₂ from that fuel. Trip Cost takes a trip distance, your car's MPG, the price per gallon and your tank size, and returns fuel needed, total cost, how many refuelling stops to expect, and range per tank. Compare Vehicles puts two cars' MPG side by side for the same monthly mileage and shows monthly and yearly savings. CO₂ Emissions estimates a year of driving for gasoline, diesel or E85.
Results update as you type, which makes it easy to test scenarios back to back: what if gas prices rise, what if you rent a less efficient car, or what a split of the fuel bill with passengers comes to. The Trip Cost, Compare Vehicles and CO₂ tabs use US units (miles, MPG, US gallons), so convert an L/100km rating to MPG first. A practical habit is to take the fuel price from a recent receipt so the estimate reflects what you actually pay at the pump.
Estimate total fuel cost and consumption for any trip by entering distance, fuel efficiency, and fuel price.
Use Fuel Efficiency instead if you want to measure your MPG from a fill-up, or Compare Vehicles to weigh two cars against each other.
Type the total miles you plan to drive — enter both legs if it is a round trip.
Input your car's MPG, from the manual or from past fill-ups. Convert an L/100km rating first: MPG ≈ 235.2 ÷ L/100km.
Add the price per gallon you expect to pay and your tank size in gallons, which is used to estimate refuelling stops.
The calculator instantly shows total trip cost, fuel needed, fuel stops, CO₂ and your range per tank.
Change the price, distance, or MPG to see how different routes, vehicles, or gas prices affect your total cost.
Fill the tank, reset the trip meter, drive normally, then fill again: the second fill-up is the fuel used for the miles on the meter.
Fuel Stops assumes you leave with a full tank and run it close to empty, so plan to stop earlier in practice.