⛽ Fuel Cost Comparison Calculator

Compare the annual fuel cost of two vehicles based on fuel economy, gas price and your annual mileage.

Annual Miles Driven

Gas Price (per gallon)

Vehicle A MPG

Vehicle B MPG

How the two annual costs are worked out

Each vehicle is priced independently, then the difference is taken:

gallons = annual miles / MPG
cost    = gallons x price per gallon
saving  = |cost A - cost B|

With the starting values, Vehicle A at 25 MPG burns 12,000 / 25 = 480 gallons, or 1,680 dollars at 3.50 a gallon. Vehicle B at 35 MPG burns 342.9 gallons, or 1,200 dollars. The 10 MPG gap is worth 480 dollars a year at that mileage and that price.

Reading the gap honestly

MPG differences are not linear in cost. Going from 15 to 20 MPG saves far more fuel than going from 35 to 40, because gallons per mile is what you actually pay for. Three inputs decide how big the answer is:

Annual miles. Double the mileage and you double the saving. A low-mileage driver rarely recovers a price premium on economy.
Pump price. This is one number for the whole year. Real prices move week to week and differ by state, brand and grade, so run the comparison again at a high and a low price to see the range.
Rated versus real MPG. Window-sticker figures assume a test cycle. Short trips, cold starts, roof boxes, towing and city traffic all pull the real number down.

This compares fuel and nothing else. Insurance, tax, tires, servicing, financing and depreciation are often larger differences between two vehicles than the fuel bill, and none of them are in here.

Frequently asked questions

How much does 10 MPG save per year?

At 12,000 miles and 3.50 a gallon, 25 MPG against 35 MPG is 480 dollars a year. The same 10 MPG step from 15 to 25 saves 1,120 dollars, because the gallons saved are what matters, not the MPG number.

Is it worth paying more for a hybrid?

Divide the extra purchase price by the annual saving this shows to get a rough payback in years, then compare that with how long you intend to keep the car. Fuel alone answers only part of the question.

What gas price should I enter?

An average for the coming year in your own area, not today's sign. The tool has no access to local pump prices, and the saving scales directly with whatever figure you type.