Use this free Fuel Cost Calculator to estimate the fuel required and total driving cost for a trip. It supports miles or kilometers, MPG or liters per 100 km, one-way and round-trip travel, and optional tolls.
How the Fuel Cost Calculator works
The Fuel Cost Calculator converts the entered distance and efficiency into a common measurement system, estimates the amount of fuel needed, multiplies that fuel by the price per unit, and then adds optional tolls or other fixed trip charges. The calculation happens directly in your browser. No account or registration is required.
For an MPG entry, fuel required in US gallons equals total miles divided by miles per gallon. For a liters-per-100-kilometers entry, liters required equals total kilometers multiplied by the consumption rate and divided by 100. For kilometers per liter, liters required equals total kilometers divided by kilometers per liter.
Fuel cost formulas
MPG formula
Gallons required = trip distance in miles ÷ MPG. Fuel cost then equals gallons required multiplied by the price per gallon.
Liters per 100 km formula
Liters required = trip distance in kilometers × L/100 km ÷ 100. Multiply the answer by the price per liter to estimate the fuel-only cost.
Kilometers per liter formula
Liters required = trip distance in kilometers ÷ km/L. The calculator converts miles to kilometers automatically whenever the selected units differ.
Worked example
Consider a 300-mile one-way trip in a vehicle that averages 30 MPG while fuel costs $3.50 per gallon. The vehicle needs 300 ÷ 30 = 10 gallons. The fuel-only cost is 10 × $3.50 = $35. If the trip includes $12 in tolls, the estimated total becomes $47. Selecting round trip doubles the travel distance and fuel requirement, but a user should enter tolls for the complete planned journey.
Choosing a realistic fuel-efficiency value
Manufacturer ratings provide a helpful reference, but actual efficiency can be lower or higher. City traffic generally uses more fuel than steady highway driving. Roof racks, heavy cargo, underinflated tires, strong wind, steep roads, cold weather and aggressive acceleration may also reduce efficiency. Recent fill-up records are often more representative than a single advertised figure.
To calculate recent MPG, divide the miles driven since the previous full tank by the gallons needed to refill the tank. For L/100 km, divide liters used by kilometers driven and multiply by 100. Use several fill-ups when possible so one unusual trip does not distort the estimate.
Planning and comparing trips
This tool can compare routes, vehicles and travel arrangements. Calculate each route separately using its distance and expected efficiency. A shorter route is not always cheaper if it involves slower traffic, hills or substantial tolls. For a shared journey, divide the total by the number of paying travelers after calculating the complete cost.
The result excludes maintenance, depreciation, insurance, parking and financing. Those costs matter when comparing driving with public transportation or air travel. The Road Trip Cost Calculator, which will join this collection later, can provide a broader estimate.
Input guide
- Trip distance: enter the distance for one direction; the round-trip option doubles it.
- Fuel efficiency: use a positive MPG, L/100 km or km/L value.
- Fuel price: enter the price for one gallon when using MPG, or one liter when using metric consumption.
- Tolls: enter fixed charges for the whole selected journey.
- Currency: choose the symbol used for displaying the result.
The Fuel Cost Calculator provides a planning estimate based on the values you supply. For official US vehicle fuel-economy comparisons, consult FuelEconomy.gov. Update the local fuel price before each trip. The Fuel Cost Calculator is most useful when its efficiency value reflects recent real driving.
Frequently asked questions about the Fuel Cost Calculator
Does this calculator support metric units?
Yes. Choose kilometers and either liters per 100 kilometers or kilometers per liter. The calculator also converts between metric and US customary distance when necessary.
Should I enter one-way or round-trip distance?
Enter the one-way distance and select the appropriate trip type. Choosing round trip doubles the entered distance automatically.
Are tolls included in fuel cost?
Tolls are not fuel expenses, but the optional field lets you include them in the total trip estimate. Enter the total toll amount expected for the selected journey.
Why might the actual cost be different?
Fuel price and vehicle efficiency can change. Traffic, weather, terrain, idling, tire pressure, driving speed and vehicle load all affect real consumption.
Can I compare two vehicles?
Yes. Calculate the trip with the first vehicle’s efficiency, record the result, and then repeat using the second vehicle’s efficiency.
