Fuel Cost Calculator

Enter the distance, fuel efficiency (km/L), and gas price (per liter) to instantly estimate the fuel cost of a car trip. Supports round trips and calculates fuel consumption and cost per kilometer automatically.

Tips

  • Check "Round trip" to automatically double the one-way distance for a there-and-back drive.
  • For a more accurate estimate, use your real-world fuel efficiency (calculated from actual refueling amount and mileage) rather than the manufacturer's catalog figure.
  • Enter the price you actually paid at the pump to get an estimate close to your receipt.
  • Add toll road fees on top of this estimate to get a fuller picture of a long-distance trip's total cost.

Frequently Asked Questions

The distance driven (doubled for round trips) is divided by fuel efficiency (km/L) to get the fuel volume consumed in liters, which is then multiplied by the fuel price per liter. The closer your inputs are to your actual efficiency and local price, the closer the estimate is to your real spending.

For a more accurate estimate, we recommend using your real-world fuel efficiency calculated from actual refueling amounts and mileage. Catalog figures (such as WLTC-mode ratings) are measured under standardized conditions, so real driving (traffic, air conditioning, etc.) tends to use more fuel than the catalog number suggests.

The formula itself is the same. Any difference in fuel economy between vehicle types should simply be reflected in the fuel efficiency (km/L) value you enter. Kei cars generally get better mileage due to their lighter weight, but this varies by model and year, so entering your own vehicle's real-world figure is recommended.

This tool covers liquid fuels such as gasoline and diesel, so it does not support estimating electricity costs for electric vehicles. If you want to compare the lifetime cost of an EV versus a gasoline car, try our EV vs. Gasoline Car Lifetime Cost Simulator elsewhere on this site.
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Side Note — Why Gas Prices Change Every Week

Gas prices fluctuate daily depending on crude oil markets, exchange rates, seasonal demand, and location, so there is no single nationwide price. Checking the local price at the station where you actually refuel, rather than a national average, gives you a fuel cost estimate that is much closer to reality.

Since 2018, manufacturer fuel efficiency figures have been standardized under the international WLTC test cycle, which combines urban, suburban, and highway driving patterns and is considered more representative of real-world conditions than the older test cycles it replaced. Even so, actual fuel economy is often lower than the catalog figure once you factor in air conditioning, traffic, and driving habits, which is why this tool recommends entering your own real-world efficiency instead.

One well-known way to cut fuel costs is "eco-driving": avoiding sudden acceleration, keeping a safe following distance to reduce braking, and easing off the accelerator early. These habits alone are said to improve fuel economy by roughly 10-20%. Checking your estimated fuel cost with this tool before a long trip can also help you plan your refueling stops and budget.