Fuel Cost Calculator
Estimate fuel use and trip cost in metric or US units, including a return journey and entered extra costs.
Last updated: November 4, 2026
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Quick summary: Estimate fuel use and trip cost in metric or US units, including a return journey and entered extra costs.
Read the complete guide
Updated reference sections in this guide are in English.
Build the estimate from your route
Choose metric or US units first, because the distance, efficiency and fuel-price labels all change together. Enter the one-way route distance. For a return trip, the calculator doubles that distance. Enter tolls and parking for the whole journey; those extra costs are added once, not once per direction. Fuel price and consumption are values you supply, not prices fetched from a station or a vehicle database.
Two fuel-efficiency conventions
US gallons = total miles ÷ miles per US gallon
Trip cost = fuel needed × price per fuel unit + entered extras
Cost per traveler = trip cost ÷ number of travelers
A higher L/100 km value means more fuel is used for the same distance. A higher mpg value means less fuel is used. The conventions therefore move in opposite directions. The US option uses US liquid gallons, not imperial gallons.
A trip with shared costs
A 300 km one-way journey
At 7.5 L/100 km, the route needs 300 × 7.5 ÷ 100 = 22.5 liters. At 1.50 per liter, fuel costs 33.75. Adding 10 for tolls and parking gives 43.75. Two travelers have an estimated share of 21.875 each before display rounding.
The same route as a return trip
Selecting Return doubles the route to 600 km and fuel to 45 liters. Fuel costs 67.50. If the entered 10 already covers tolls and parking for the entire return journey, the total is 77.50. Adjust that extras field if the actual return charges differ.
A US-unit check
For 300 miles at 30 miles per US gallon, the estimate is 10 US gallons. At 3.50 per gallon with no extras, fuel costs 35.00.
Check this scenario in the calculator:
- Units
- Metric: km, L/100 km, price per liter
- One-way distance (km)
- 300
- Fuel consumption (L / 100 km)
- 7.5
- Price per liter
- 1.5
- Journey
- One way
- Tolls and parking for the whole trip
- 10
- Travelers sharing the cost
- 2
- Currency (display only)
- USD — US dollar
Make the consumption assumption realistic
Use a consumption figure that reflects the kind of route you expect. City traffic, sustained speed, hills, weather, loading and vehicle condition can affect fuel use. A useful comparison is to repeat the calculation with a higher consumption assumption while leaving distance and price unchanged. That shows the effect of efficiency without mixing several changes together.
What the trip total leaves out
The estimate excludes depreciation, insurance, maintenance, charging costs, time and any costs you do not enter. It assumes the same consumption and fuel price across the entire route. The travelers field divides costs equally; it does not allocate different distances or expenses to different people. A return journey is modeled as twice the same one-way distance.
Fuel-cost questions
Is a gallon the same in every country?
No. The US mode explicitly uses US liquid gallons. Use the unit converter when you need to distinguish US and imperial gallons.
Are tolls doubled for a return journey?
No. Enter the entire journey’s tolls and parking yourself. Only the distance is doubled.
Does selecting a different currency look up fuel prices?
No. It changes the display currency only. Both fuel prices and extra costs remain your inputs.