How trip fuel cost is calculated
The fuel cost of a trip depends on how far you drive, how efficient your car is, and the price of gas. The formula is cost = (distance ÷ mpg) × price per gallon. A 300-mile drive in a car that gets 25 mpg uses 12 gallons; at $3.50 per gallon that is 12 × 3.50 = $42.00.
How to use this calculator
Enter the distance in miles, your car's fuel economy in miles per gallon, and the current gas price per gallon. The result is the estimated fuel cost, with the gallons used shown below. If you don't know your mpg, work it out with the fuel economy calculator first. For a route measured in kilometres, convert the distance with the km to miles calculator.
Worked example
A 600-mile round trip in a 30 mpg car at $4.00 a gallon: 600 ÷ 30 = 20 gallons, × $4.00 = $80.00. Highway driving usually returns better mpg than city driving, so your real cost may be a little lower on a long freeway trip. To estimate how long a download for the road takes, see the download time calculator.
Remember the calculator prices one direction only, so double the distance for a round trip. Speed matters too: most cars are most efficient around 50–60 mph, and holding 80 mph instead can burn 15–20% more fuel, quietly adding $10–$15 to that 600-mile trip. Charging costs instead of fuel are handled by the electricity cost calculator.
Frequently asked questions
- How do I calculate the gas cost of a trip?
- Divide the distance by your mpg to get gallons used, then multiply by the price per gallon. 300 miles ÷ 25 mpg × $3.50 = $42.00.
- What does a 300-mile trip cost at 25 mpg?
- At $3.50 per gallon it costs $42.00, using 12 gallons of fuel.
- Should I use city or highway mpg?
- Use the figure that matches your trip. Highway mpg is usually higher, so a freeway trip costs a bit less than the city estimate.
- How do I find my car's mpg?
- Divide the miles you drove by the gallons it took to refill. The fuel economy calculator does this for you.
- Does this work for diesel or an electric car?
- It works for any fuel sold by the gallon, so enter the diesel price and your diesel mpg and the result is correct. For an EV it will not work, because charging is billed per kWh — use the electricity cost calculator instead.