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Fuel Cost Calculator for a Trip
Enter the distance, your vehicle's fuel economy in the units you know, and the price of fuel. The calculator shows how much fuel the trip needs, what it will cost, and the share per passenger.
How the trip cost is worked out
The calculation converts everything to kilometres and litres, finds the fuel burned, and then multiplies by the price per litre.
Fuel used = distance × (litres per 100 km) ÷ 100
Cost = fuel used × price per litre
If the economy is given as miles per gallon, it is first turned into litres per 100 km using exact unit definitions. With 7.5 L/100 km over 400 km the car needs 30 litres, which at 1.60 per litre costs 48.00. Each of two passengers pays 24.00.
If you enter the price per gallon, the tool converts it to a litre price first. The page shows the fuel needed in litres and in the unit of the price, so you can match it against the pump display.
Choosing realistic inputs
Manufacturer figures are measured under standard test conditions, and many drivers see higher consumption in real use. A better figure is your own average from several full tanks, which the gas mileage calculator can produce. Motorway speeds above a vehicle's efficient range, roof boxes, a heavy load, air conditioning, winter tyres and cold weather all raise consumption.
For the price, use the amount you expect to pay at the pumps on the route. Prices differ between motorway services and town stations, and between fuel grades. If the trip crosses a border, run the calculation separately for each leg with its own price and economy.
What the result leaves out
- Tolls and parking. Not included, and often significant on long journeys.
- Wear and depreciation. Tyres, servicing and the fall in vehicle value depend on distance but are not fuel.
- Detours and idling. The distance is what you type. Add extra for city driving, diversions and waiting.
- Electric and hybrid vehicles. Plug-in energy costs follow kilowatt-hours, not litres.
Reimbursement rules for business mileage are set by employers or tax authorities and are usually a flat rate per distance, not the actual fuel cost shown here.
Sharing the cost fairly
Dividing fuel evenly is straightforward and is shown as the cost per person. Some groups also contribute for the driver's wear, tolls and parking, or split by the number of passengers excluding the owner of the car. Agree the rule before the trip, because the maths is simple but the expectations are not. The per-kilometre and per-mile lines help when you need to settle a smaller leg of the journey.
For regular commutes, multiply the cost of one day by the number of days worked to compare driving with a season ticket or a lift-share arrangement.
Worked example
Two friends drive 400 km in a car that uses 7.5 litres per 100 km, with fuel at 1.60 a litre, and split the cost.
Inputs
| Trip distance | 400 |
|---|---|
| Distance unit | Kilometres |
| Trip type | One way |
| Fuel economy | 7.5 |
| Fuel economy is in | Litres per 100 km |
| Fuel price | 1.6 |
| Price is per | Litre |
| People sharing the cost | 2 |
Result
30.0 litres for 400 km.
| Fuel needed (litres) | 30.00 |
|---|---|
| Fuel needed (litres) | 30.00 |
| Total distance | 400.0 km (248.5 miles) |
| Cost per person | 24.00 |
| Cost per kilometre | 0.120 |
| Cost per mile | 0.193 |
- Real consumption changes with speed, load, traffic, terrain and temperature. Add a margin if the trip is long or the route is hilly.
Accuracy note: Results are calculated in your browser from the values you enter. Check anything that matters for legal, academic or financial purposes against the official source.
Frequently asked questions
How do I calculate the fuel cost of a trip?
Divide the distance by your fuel economy to find the fuel needed, then multiply by the price per unit of fuel. The calculator handles the unit conversions between kilometres, miles, litres and gallons.
Which fuel economy value should I use?
Use your own measured average if you have one. Otherwise use the official combined rating, and add a margin because everyday driving often uses more fuel than test conditions suggest.
Does the round trip option double the cost?
Yes. It doubles the distance, so the fuel and the cost double as well. The one-way distance you enter is not changed, and the total distance row shows the doubled figure.
Can I enter the price per gallon with a metric car?
Yes. Pick the price unit separately from the economy unit. The tool converts the price to a cost per litre before multiplying by the litres used.
Are tolls and maintenance included?
No. The result is fuel only. Add tolls, parking and a per-distance allowance for wear separately if you want the full running cost of the journey.