Free Tool · Road distance included

Trip fuel cost calculator: what will this journey cost in fuel?

Find out how much a car journey will cost in petrol, diesel or electricity. Enter where you start and where you are going for the road distance and driving time, add your car's fuel economy in mpg (UK or US), L/100 km or km/L and the price you pay, and see the total for one way or a return trip, the cost per mile or kilometre and each person's share. Free, no signup.

Trip fuel cost calculator

Enter a distance, or two places, to see the cost.

Road distances from the OSRM route planner using OpenStreetMap data; place search by Nominatim. Fuel prices are examples: type in what you pay. Real consumption is usually higher in towns, at motorway speeds and in cold weather.

Fuel economy conversions

L/100 kmmpg (UK)mpg (US)km/L
4.070.658.825.0
5.056.547.020.0
6.047.139.216.7
7.040.433.614.3
8.035.329.412.5
10.028.223.510.0
12.023.519.68.3

Lower L/100 km is better; higher mpg and km/L are better. To convert, mpg (UK) = 282.5 ÷ L/100 km, and mpg (US) = 235.2 ÷ L/100 km.

Ways to spend less on fuel

  • Drive smoothly: gentle acceleration and braking can save a noticeable share of fuel.
  • Slow down a little: on motorways, fuel use rises quickly above about 90 km/h (55 mph).
  • Check the tyres: under-inflated tyres increase rolling resistance.
  • Lose the weight and drag: empty roof boxes and bike racks when you are not using them.
  • Fill up off the motorway: fuel at motorway services usually costs more.

Frequently asked questions

How do I work out the fuel cost of a journey?

Divide the distance by your car's fuel economy to get the fuel used, then multiply by the fuel price. For 300 km at 6.5 L/100 km and 1.70 a litre: 300 × 6.5 ÷ 100 = 19.5 litres, × 1.70 = 33.15. The calculator does this for you, with the road distance found from two places.

Is a UK gallon the same as a US gallon?

No. A UK (imperial) gallon is 4.546 litres and a US gallon is 3.785 litres, so the same car does about 20% more miles per gallon in UK figures. 40 mpg (UK) equals about 33 mpg (US) and 7.1 L/100 km. Choose the right unit in the calculator.

How do I find my car's real fuel economy?

Fill the tank, reset the trip counter, drive normally, then fill up again. Divide the distance driven by the litres or gallons you put in. The figure on the car's dashboard is a good guide but is often a little optimistic.

How much does it cost to charge an electric car for a trip?

Switch to "Electric", enter the car's efficiency (shown on the dashboard in miles/kWh or kWh/100 km) and the price per kWh. Charging at home is usually far cheaper than at rapid public chargers, so use the price you will actually pay.

How should we split fuel costs for a car share?

A common way is to divide the fuel cost evenly between everyone in the car, including the driver; set "People sharing". Some groups also add a little for wear, parking or tolls, which the calculator does not include.

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