Fuel Cost Calculator
Work out the fuel cost of any journey or daily commute. Pick your units and fuel type, add a round trip, split between passengers, and see per-trip, weekly, monthly and yearly costs plus CO₂.
Journey details
Commute cost over time
Estimates based on the figures you enter. Real-world fuel use varies with driving style, traffic, load, terrain, air-con and weather. CO₂ uses ~2.31 kg/L petrol and ~2.68 kg/L diesel.
Disclaimer: A planning estimate only, not a guarantee of actual fuel spend.
Estimate a journey from measured fuel economy
Enter journey distance, fuel economy and fuel price in the units shown. Select the correct US or imperial gallon when using MPG. Add a round trip only if your entered distance is one-way. Passenger splitting divides the journey cost by the number of people sharing it.
Use a realistic consumption figure for your vehicle and trip. A laboratory rating or an empty-vehicle estimate can understate use in traffic, towing, steep terrain or cold weather. This tool calculates from the values you enter; it does not retrieve live pump prices, traffic or a vehicle’s measured fuel use.
Fuel cost formulas and a worked example
- Using km/L: litres used = distance in km ÷ km per litre.
- Using L/100 km: litres used = distance in km × L/100 km ÷ 100.
- Fuel cost = litres used × price per litre.
- Cost per person = total fuel cost ÷ people sharing.
For a 300 km journey at 15 km/L, fuel used is 300 ÷ 15 = 20 L. At an example price of 1.50 per litre, fuel costs 30. Three people sharing equally pay 10 each. A return journey of the same distance doubles those quantities if conditions and fuel economy are unchanged.
Use the commute and emissions results carefully
For a commute, check whether the chosen trip count represents one-way or return journeys. Monthly and annual totals depend on the tool’s period assumptions; use your actual working days when budgeting for holidays or irregular attendance.
The CO₂ result estimates combustion emissions from fuel volume. It does not include fuel production, vehicle manufacture or a complete lifecycle assessment. Petrol and diesel have different factors, and actual fuel blends vary. Do not use this result as an audited emissions inventory.
Frequently asked questions
What is the difference between MPG and L/100 km?
MPG is distance per gallon, so a higher number means less fuel used for a fixed journey. L/100 km is fuel per distance, so a lower number means less fuel. Do not enter one as the other.
Why does US versus UK MPG matter?
A US liquid gallon is 3.785411784 L and an imperial gallon is 4.54609 L. An MPG figure based on the larger imperial gallon is numerically higher for the same consumption.
Does fuel cost include tolls, parking and accommodation?
No. Add those separately or use the trip-cost calculator. Fuel alone is not the full cost of owning or using a vehicle.
How can I get a better consumption input?
Over a representative distance, record fuel added and distance travelled, using a consistent fill method. Divide distance by litres for km/L, or multiply litres by 100 and divide by distance for L/100 km. Several observations help account for variation.