Fuel Cost Calculator
What a trip costs in fuel, from the distance, your car's fuel economy and the fuel price, with each person's share.
Result…
How it's calculated
Fuel used = distance × fuel per distance L/100 km: litres = km × L/100 km ÷ 100 · mpg: gallons = miles ÷ mpg Cost = fuel used × price · Per person = cost ÷ people
Works in litres inside, using exact factors: 1 mile = 1.609344 km, 1 US gallon = 3.785411784 L and 1 UK (imperial) gallon = 4.54609 L. So you can mix units: a distance in km, a fuel economy in UK mpg and a price per litre all work together. A round trip doubles the distance. Use your car's real average if you know it; official figures are often better than on the road. To work out your car's fuel economy from a fill-up, use the gas mileage calculator.
Your numbers, step by step
About the Fuel Cost calculator
This fuel cost calculator works out what a journey costs in fuel from three things: how far you are going, how much fuel your car uses, and the price of fuel. Distances can be in kilometres or miles, fuel economy in L/100 km, km/L, US mpg or UK mpg, and the price per litre, per US gallon or per UK gallon, in any mix. Tick a round trip to double the distance, and enter how many people are sharing to see each person's share. It is handy for planning a road trip, splitting costs with friends, or comparing driving with another way of travelling. The steps show each conversion with your numbers, using exact factors: 1 mile is 1.609344 km, a US gallon is 3.785411784 litres and a UK gallon is 4.54609 litres. To find your car's real fuel economy first, use the gas mileage calculator.
How to use it
- Choose “One way” or “Round trip” under “Trip”.
- Enter the “Trip distance” and pick kilometres or miles.
- Enter your car's “Fuel economy” and choose its unit: L/100 km, km/L, mpg (US) or mpg (UK).
- Enter the “Fuel price” and say whether it is per litre, per US gallon or per UK gallon.
- Set “People sharing the cost” if you are splitting it, then read the total, each person's share and the cost per km and per mile.
Worked example
A 180 km drive there and back is 360 km. At 6.5 L/100 km the car uses 360 × 6.5 ÷ 100 = 23.4 litres. At 1.70 per litre that is 23.4 × 1.70 = 39.78, or 13.26 each for 3 people, about 0.11 per km. In miles: 300 miles at 30 US mpg uses 300 ÷ 30 = 10 US gallons, and at 3.50 per US gallon the fuel costs 35, about 0.117 per mile.
Updated
Questions people ask
How do I calculate the fuel cost of a trip?
Work out the fuel used, then multiply by the price. With L/100 km, fuel = distance × L/100 km ÷ 100; with mpg, gallons = miles ÷ mpg. Then cost = fuel × price per litre or per gallon.
Can I use UK mpg with a price per litre?
Yes. UK drivers often quote miles per UK gallon but buy fuel by the litre. Pick mpg (UK) and a price per litre, and the calculator converts with 1 UK gallon = 4.54609 litres.
What is the difference between US and UK mpg?
The gallons differ. A US gallon is exactly 3.785411784 litres and a UK gallon is 4.54609 litres, so the same car shows a higher mpg in UK gallons. Mixing them up gives an answer about 20% out. The fuel economy calculator converts between them.
How do I split fuel costs between passengers?
Enter the number of people in “People sharing the cost”. The total is divided evenly, so 39.78 shared by 3 people is 13.26 each.
Why is my real fuel cost different from the estimate?
Fuel use changes with speed, traffic, hills, load, air conditioning and the weather, and official economy figures are often better than real driving. Use the average your own car gets, and treat the result as an estimate of fuel only, not tolls, parking or wear.