Fuel Cost Calculator

Estimate the fuel cost of a car journey from the distance, your car's fuel economy and the fuel price, in km or miles, litres or gallons, and split it per person.

How to use the fuel Cost Calculator

  1. Enter the trip distance and choose kilometres or miles. Tick Return trip to double it.
  2. Enter your car's fuel economy and choose the unit you know it in: L/100 km, km/L, or US or UK miles per gallon.
  3. Enter the fuel price and whether it is per litre, per US gallon or per UK gallon.
  4. Optionally split the cost between passengers, and choose your currency.
  5. The result updates instantly as you type. There is no button to press.
  6. Use Copy result to copy the figures, or Copy link to share a link that reopens the fuel Cost Calculator with the same inputs.

How it works

Before a road trip, a commute decision or a car-share arrangement, it helps to know what the fuel will actually cost. This calculator combines the three things that matter: how far you're going, how much fuel your car uses, and what fuel costs. It works in any mix of units, so you can use miles with UK mpg, kilometres with L/100 km, or whatever your car's dashboard and the local pump show.

Everything is converted to kilometres and litres first. Fuel economy in distance-per-fuel units such as mpg and km/L is turned into litres per kilometre, since a car that does 30 mpg needs the reciprocal, 1/30 of a gallon per mile. Multiplying by the distance gives the fuel needed, and multiplying by the price per litre gives the cost.

Real-world consumption is usually worse than official ratings, often by 10–25%, especially at motorway speeds, with a roof box, in cold weather or with a heavy load. For a cautious budget, use the figure from your car's trip computer rather than the brochure. To compare with public transport or flights, remember that the car's cost is shared between everyone in it. Use Split between to see the cost per person.

Formula

fuel (L) = distance (km) × L/100 km ÷ 100 L per km = 1 / (km/L) = 3.785 / (US mpg × 1.609) = 4.546 / (UK mpg × 1.609) cost = fuel (L) × price per litre cost per person = cost / people

Example

A 300 km trip in a car using 7.5 L/100 km needs 300 × 7.5 ÷ 100 = 22.5 litres. At 1.85 per litre that costs 41.63, or 0.14 per km. As a return trip it's 83.25, and split between three people about 27.75 each. In US units, a 200-mile drive at 28 mpg with gas at $3.50 a gallon uses 7.14 gallons and costs about $25.00.

Frequently asked questions

How do I find my car's fuel economy?

Check the trip computer, or fill the tank, reset the trip meter, drive normally, refill and divide the distance by the fuel added. That's usually more accurate than the official rating.

Does this include tolls and parking?

No, only fuel. Add tolls, parking, and wear and tear separately. Many mileage allowances, such as business mileage rates, include those running costs as well as fuel.

Can I use it for an electric car?

Not directly. For an EV, multiply the distance by the kWh per km (or mile) and by the electricity price per kWh.