Fuel Savings Calculator

Divide your annual miles by the vehicle's mpg to get gallons used, then multiply by the price per gallon. At 12,000 miles and 20 mpg that is 600 gallons, which at $3.50 is $2,100. The savings is the difference between the two yearly costs.

Fuel use depends on gallons, not on mpg directly, and mpg is an inverse measure. Going from 15 to 20 mpg saves far more fuel than going from 40 to 45 mpg over the same miles, because the low end burns many more gallons to begin with.

Use a recent local price per gallon. You can re-run the numbers with a higher price to see how much more a thirsty vehicle would cost if prices climb, since savings scale directly with the price you enter.

It compares two gasoline mpg figures. For a hybrid, use its combined mpg rating. For a fully electric car, convert its efficiency to an equivalent mpg or compare energy cost separately, since it does not burn gallons.

No. This tool isolates fuel cost so the comparison is clean. Total cost of ownership also includes maintenance, insurance, depreciation and financing, which can outweigh fuel differences on a pricier car.

Yes. Annual miles, gas price, current mpg and new mpg must each be a positive number, or the tool shows a prompt to fix the entry. Blank fields also stop the calculation until every box is filled.

Yes. If the new mpg is lower, the annual savings and gallons saved come out negative, showing the more efficient car is the one you already drive. The tool does not stop you from comparing in either direction.

The engine keeps full precision internally. The display rounds money to cents and gallons to a whole number, so a fractional gallon result is shown rounded even though the exact value drives the cost figures.

Yes. The math runs in your browser and nothing you type is uploaded, so your mileage and price stay on your device.