Trip Fuel Cost Calculator

Work out the fuel and cost for a trip, with round trip and cost sharing, in any units and any currency, such as dinar, dollar or riyal.

Distance

Distance unit

Fuel efficiency

Efficiency unit

Fuel price (in the chosen currency)

Currency

Price per

Round trip

People sharing the cost

Enter the values to see the result here.

Formula

Everything is converted to kilometres and litres first. Efficiency becomes litres per 100 km, $e$ :

e = \frac{100}{\text{km/L}},\qquad e = \frac{235.215}{\text{mpg}_{US}},\qquad e = \frac{282.481}{\text{mpg}_{UK}}

Then, with distance $d$ in km (doubled for a round trip) and price $p$ per litre:

\text{litres} = \frac{d\,e}{100},\qquad \text{cost} = \text{litres} \times p,\qquad \text{per person} = \frac{\text{cost}}{n}

A price per gallon is divided by 3.7854 (US) or 4.5461 (imperial) to give a price per litre.

Worked example

A round trip to a city 450 km away, car using 8.5 L/100 km, fuel at 2.33 per litre, four people sharing.

Total distance: $2 \times 450 = 900$ km.
Fuel: $900 \times 8.5 / 100 = 76.5$ L.
Cost: $76.5 \times 2.33 = 178.25$ .
Per person: $178.25 / 4 = 44.56$ .

That is 0.198 per kilometre for the car.

Common mistakes

Entering km/L in the L/100 km box. A figure of 12 is a good km/L but a terrible L/100 km.
Forgetting the return leg.
Using a US gallon price with a UK mpg rating.
Dividing the fuel cost between passengers but not counting the driver as a person.

Frequently asked questions

How do I convert mpg to L/100 km?

Divide 235.215 by the US mpg figure, or 282.481 by the UK mpg figure. 30 mpg (US) is 7.84 L/100 km and 30 mpg (UK) is 9.42 L/100 km. They differ because the gallons differ.

Why is my real consumption higher than the car's rating?

Lab tests use gentle driving. Motorway speeds above 110 km/h, heavy loads, roof boxes, cold weather and air conditioning can each add 10 to 20%. Use your own tank-to-tank figure for the best estimate.

How do I find my car's real consumption?

Fill the tank, reset the trip meter, drive normally, then refill. Litres added divided by kilometres driven, times 100, is your L/100 km.

Should the cost include wear and tyres?

This tool counts fuel only. Running cost with tyres, servicing and depreciation is commonly two to three times the fuel cost per kilometre.