Fuel Savings Calculator
A more efficient car costs less to fuel, but how much less over a year? This fuel savings calculator compares two vehicles at the same annual mileage and gas price, so you can see the yearly difference in dollars. It is the figure to weigh against a higher sticker price when you are deciding whether better MPG is worth paying for.
Calculate
Default result: $1,125.00
Fuel Savings Calculator · Materials
calculators.dev
Annual fuel saving (new car)
15000 × 3.5 × 20 × 35
Shopping list
- Current car — yearly fuel cost
- $2,625.00
- New car — yearly fuel cost
- $1,500.00
Est. total
$1,125.00
Estimate — confirm w/ supplier · calculators.dev
Reviewed by the calculators.dev team · Last updated 2026-06-24
Formula reviewed against U.S. EPA / fueleconomy.gov — annual fuel cost from MPG, miles, and fuel price
How to calculate
Enter how many miles you drive in a year, the price per gallon, and each car's MPG. The calculator works out each car's yearly fuel cost as annual miles ÷ MPG × price, then subtracts the more efficient car's cost from the other. At 15,000 miles a year and $3.50 per gallon, moving from 20 MPG to 35 MPG saves $1,125 a year. To estimate payback, divide the price difference by the annual saving.
yearly fuel cost = (annual miles ÷ MPG) × price per gallon, calculated for each car. saving = current car's cost − new car's cost. For 15,000 miles at $3.50/gal: a 20 MPG car costs $2,625 and a 35 MPG car costs $1,500, a saving of $1,125 a year.
Example calculation
Driving 15,000 miles a year at $3.50 per gallon, a 20 MPG car burns $2,625 of fuel while a 35 MPG car burns $1,500 — a yearly saving of $1,125 from the more efficient car. Over several years that difference adds up and can offset a higher purchase price.
- savings
- $1,125.00
- annualCostA
- $2,625.00
- annualCostB
- $1,500.00
Assumptions
- Both cars are assumed to drive the same annual mileage at the same fuel price.
- MPG is treated as a constant; real fuel economy varies with driving style and conditions.
- The comparison is fuel only — it ignores price, insurance, maintenance, and resale differences between the cars.
Common mistakes
- Comparing fuel cost alone — a big fuel saving can be outweighed by a higher purchase price or insurance.
- Using EPA-best MPG figures rather than the real-world numbers you actually see.
- Forgetting that switching from gas to a hybrid or EV changes the cost basis entirely (electricity vs gallons).
Frequently asked questions
How much will I save on fuel with a better MPG car?
Multiply your annual miles by the price per gallon, divide by each car's MPG, and subtract. Going from 20 to 35 MPG at 15,000 miles a year and $3.50/gal saves about $1,125 per year.
Does a fuel saving justify a more expensive car?
Divide the price difference by the annual fuel saving to find the rough payback in years. If you keep the car longer than that, the better MPG pays for itself — but factor in insurance and maintenance too.
What MPG figures should I enter?
Use realistic, real-world MPG for the driving you do, not the optimistic best-case EPA highway number, or the saving will be overstated.
Does this work for hybrids or EVs?
It compares gasoline cars by MPG and gas price. For a hybrid or EV you would need to compare cost per mile, since an EV runs on electricity rather than gallons.