Your results
| Car | Annual fuel cost |
|---|---|
| Car A | $— |
| Car B | $— |
How the comparison works
Both cars are assumed to travel the same annual distance, so the only thing that changes the fuel bill is their fuel economy. The calculator works out each car's yearly fuel cost, then subtracts one from the other to show the difference. The five-year figure simply multiplies that yearly difference by five, ignoring changes in fuel prices over time.
In US units, a car's annual fuel cost is annual miles ÷ MPG × $/gal. In metric it is annual km × (L/100km ÷ 100) × $/L. The calculator converts to a common base internally, so the comparison is identical no matter which units you choose.
A difference of a few MPG can add up to hundreds or thousands of dollars over the life of a car. This is one of the easiest ways to compare the running costs of two otherwise similar vehicles — but remember that insurance, servicing, depreciation and purchase price also matter when you make a real decision.
The fuel type labels are for your reference only and do not change the calculation. They simply help you keep track of which car is which. Note that different fuels are usually priced differently — diesel and premium petrol, for example, often cost more per gallon than regular petrol — so for the most realistic comparison, use the actual price of the fuel each car takes. If one candidate is a hybrid or an electric vehicle, try our EV charging calculator instead, since those cars use a different efficiency measure.
Tip: run the comparison with your own real-world fuel economy rather than the official rating for the most realistic estimate of what each car will actually cost to run.
Related tools
- Commute cost calculator — see what your own driving costs.
- Trip cost calculator — fuel cost for a single journey.
- EV charging calculator — compare an EV against a petrol car.