Fuel Cost Calculator
Enter the distance, your car's fuel economy and the price of fuel to estimate the litres used, the total cost and each person's share of a shared journey.
A UK gallon is 4.54609 litres, and UK miles per gallon figures use that gallon. US gallons are smaller, so a US mpg figure gives a different result here.
Worked examples
Cost of a 300 mile trip
300 miles at 40 miles per gallon, with fuel at £1.50 per litre
About 34.10 litres used, and a fuel cost of £51.14.
UK miles per gallon use the imperial gallon of 4.54609 litres, so 7.5 gallons becomes 34.10 litres before the price is applied.
Short trip in a small car
120 miles at 50 miles per gallon, with fuel at £1.40 per litre
About 10.91 litres used, and a fuel cost of £15.27.
The calculation is trip distance divided by fuel economy, converted to litres, then multiplied by the price per litre.
About Fuel Cost Calculator
A fuel cost calculator estimates how much fuel a journey will use and what it will cost. Enter the trip distance in miles or kilometres, your car's fuel economy in UK miles per gallon or litres per 100 kilometres, and the price of fuel per litre or per gallon. The result shows the distance, the litres or gallons needed, the total cost and the cost per person if you are sharing the journey with others. Whether you are planning a weekend away or a daily commute, the calculator gives a clear starting point for the budget.
UK fuel economy figures use the imperial gallon, which holds 4.54609 litres, and the calculator uses that size whenever you enter miles per gallon or a price per gallon. US gallons are smaller, so a figure taken from a US source gives a different answer. The figures are estimates only and are not advice, because actual fuel use changes with speed, weather, load and driving style. Use the return journey option to double the distance for a round trip, and check the result against your own fuel records.
How to use Fuel Cost Calculator
- Enter the trip distance and choose miles or kilometres.
- Choose how your fuel economy is measured, then enter the figure.
- Enter the fuel price and choose whether it is per litre or per UK gallon.
- Enter the number of people sharing the cost, then copy the result.
Common uses
- Estimating the cost of a road trip before setting off
- Splitting fuel costs fairly between friends who share a car
- Comparing the running cost of two vehicles over the same journey
- Working out how much a commute costs in fuel each month
Frequently asked questions
How do I work out the fuel cost of a journey?
Find the litres used by multiplying the distance in kilometres by the litres per 100 kilometres figure, then dividing by 100. Multiply the litres by the price per litre to get the cost. For example, 193 kilometres at 7 litres per 100 kilometres uses about 13.5 litres, which costs about £19.60 at £1.45 a litre. The calculator does these steps for you.
How do I convert miles per gallon to litres per 100 km?
Divide 282.48 by the miles per gallon figure. This works because a UK gallon is 4.54609 litres and a mile is 1.609344 kilometres. For instance, a car that does 40 mpg uses about 7.06 litres per 100 kilometres. To go the other way, divide 282.48 by the litres per 100 kilometres figure, which gives the mpg.
Why does the calculator use UK gallons?
UK fuel economy figures, and many UK prices quoted per gallon, are based on the imperial gallon. A UK gallon is about 4.55 litres, while a US gallon is about 3.79 litres. Using the wrong gallon would change the answer by around a fifth, so the calculator uses the UK size whenever a gallon is involved. If your figures come from a US source, convert them to litres before you enter them.
Can I split the fuel cost between several people?
Yes. Enter the number of people sharing the journey and the calculator divides the total fuel cost by that number. This suits car shares, group trips and days out. If one person drives more than the others, or someone covers tolls or parking, you may want to agree a different split. The calculator only shares the fuel cost equally.
How accurate is a fuel cost estimate?
The estimate is only as good as the figures you enter. Real fuel use changes with speed, traffic, weather, the load in the car, tyre pressure and how smoothly you drive. Trip computers and averages from several fill-ups usually give a better guide than a single advertised figure. Use the result to plan and compare, and treat it as an estimate rather than a fixed cost.