About the fuel cost calculator
The fuel cost calculator estimates how much fuel a trip will use and what it will cost. Enter the distance, your vehicle's fuel efficiency and the fuel price, in kilometres or miles, and in the units your car or pump uses.
It also shows the cost per kilometre or mile and, for shared trips, the cost per person. Efficiency can be entered as litres per 100 km, kilometres per litre, or miles per US or UK gallon.
Who should use the fuel cost calculator
- Drivers planning a road trip or comparing the cost of driving with other transport.
- Car-sharers and colleagues splitting fuel costs.
- Anyone comparing vehicles with efficiency quoted in different units.
How to use the fuel cost calculator: what each input means
- Trip distance
- In kilometres or miles; can be one way or a round trip.
- Fuel efficiency
- Litres per 100 km, km per litre, MPG (US) or MPG (UK). Note that a US gallon and a UK gallon are different sizes.
- Fuel price
- Per litre, per US gallon or per UK gallon. The default is an example, so enter today's price.
- People
- The number of people sharing the cost.
How the fuel cost calculator works: method and formula
The calculator converts everything to a common basis: distance in kilometres, efficiency in litres per 100 km and price per litre. Fuel used equals distance times efficiency divided by 100, and cost equals fuel used times price per litre.
Unit conversions use exact definitions: 1 mile = 1.609344 km, 1 US gallon = 3.785411784 litres and 1 UK (imperial) gallon = 4.54609 litres.
- Fuel used
- litres = km × (L/100 km) ÷ 100
- Cost
- cost = litres × price per litre
- MPG to L/100 km
- L/100 km = 100 × litres per gallon ÷ (1.609344 × MPG)
How to read your fuel cost calculator result
Use the cost-per-distance figure to compare driving with other options. Real consumption changes with speed, load, temperature, traffic and driving style, so treat the result as an estimate and add a margin for a long trip.
If your car shows average consumption on its trip computer, use that rather than the manufacturer's official figure, which is usually lower than real-world use.
Fuel Cost Calculator worked example
A 250 km trip in a car that uses 7.5 litres per 100 km, with fuel at 1.70 per litre (an example price).
- Fuel used = 250 × 7.5 ÷ 100 = 18.75 litres.
- Cost = 18.75 × 1.70 = 31.88.
- Cost per km = 0.128; the same efficiency is 31.4 MPG (US) or 37.7 MPG (UK).
About 18.75 litres and 31.88 in fuel for the trip.
Practical uses of the fuel cost calculator
- Budgeting for a holiday drive or a commute.
- Splitting fuel costs between passengers.
- Converting between MPG and L/100 km.
Assumptions and limitations of this calculator
- Assumes a constant average consumption. Real use varies with conditions.
- Fuel only. Tolls, parking, wear and depreciation are not included.
- For electric vehicles, a different calculation using kWh per 100 km and electricity price is needed.
Notes for different countries and units
- Efficiency is quoted differently around the world: litres per 100 km in much of Europe, miles per imperial gallon in the UK (although fuel is sold in litres), miles per US gallon in the US, and commonly kilometres per litre in India and Pakistan. Enter whichever you know and the calculator converts exactly. A US gallon (3.785 L) and a UK gallon (4.546 L) are different sizes.