Fuel Cost Calculator
Work out what a journey costs in fuel from the distance, your car's economy and the pump price, then split it between passengers.
How the fuel cost is worked out
Every fuel cost sum has the same three parts: how far you are going, how thirsty the car is, and what fuel costs at the pump. Divide distance by economy to get the fuel used, then multiply by the price. The only thing that trips people up is units, and the calculator above handles all of them - miles or kilometres, UK or US mpg or litres per 100 km, and a price set per litre or per gallon.
A worked example
Say you are driving 300 miles in a car that does 45 mpg (UK), with fuel at 1.45 per litre. That journey uses 300 / 45 = 6.67 imperial gallons, which is 30.3 litres. At 1.45 a litre the trip costs about 44. Share it between four people and that is roughly 11 each - often cheaper and greener than everyone driving separately.
Watch the gallon
The single biggest source of error is mixing up gallons. A UK gallon is 4.546 litres; a US gallon is only 3.785. So a car rated at 40 mpg in Britain is about 33 mpg in American terms, even though nothing about the car changed. If you took your economy figure off a US window sticker, pick mpg (US); a British car handbook uses mpg (UK); and most of Europe quotes L/100km, where a lower number is better.
Handy reference points
- A small efficient petrol car: roughly 50 to 60 mpg (UK), or about 5 L/100km.
- A typical family SUV: around 35 to 40 mpg (UK), or 7 to 8 L/100km.
- 1 UK gallon = 4.546 litres; 1 US gallon = 3.785 litres; 1 mile = 1.609 km.
Comparing two cars or two routes? The percentage calculator makes the difference easy to express, and if you are splitting more than just fuel on a trip, the bill splitter handles the rest.