How to use the fuel cost calculator
- Type the distance one way, and tick "Return trip" if you're coming back.
- Type your car's fuel economy and choose how it's measured. US cars usually show MPG in US gallons, UK cars MPG in UK gallons, and Canadian and Australian cars litres per 100 km.
- Type the fuel price at the pump, per US gallon, UK gallon or litre.
- Split the cost between passengers if you're sharing.
How it's calculated
We work out how many litres the trip uses, then multiply by the price per litre. A US gallon and a UK gallon are different sizes, so an MPG figure from a UK car isn't the same as one from a US car.
1 US gallon = 3.785411784 litres 1 UK gallon = 4.54609 litres 1 mile = 1.609344 km
MPG fuel = miles ÷ MPG, in that country's gallons
L/100 km fuel = km × L/100 km ÷ 100
km/L fuel = km ÷ km/L
Cost fuel in litres × price per litre
Worked examples
US: 300 miles at 30 MPG (US), $3.50 a US gallon
300 ÷ 30 = 10 US gallons × $3.50 = $35.00 return trip: $70.00
UK: 200 miles at 45 MPG (UK), £1.40 a litre
200 ÷ 45 = 4.44 UK gallons = 20.2 litres × £1.40 = £28.29
Australia: 500 km at 6.5 L/100 km, A$1.90 a litre
500 × 6.5 ÷ 100 = 32.5 litres × A$1.90 = A$61.75 split between 2 = A$30.88 each
Frequently asked questions
Why is UK MPG higher than US MPG for the same car?
A UK gallon holds about 20% more than a US gallon, so a car goes further on one. 30 MPG in US gallons is about 36 MPG in UK gallons.
Can I use this for an electric car?
Not directly: it works in fuel volumes. For an electric car, multiply the kWh the trip uses by your price per kWh.
Does it include tolls, parking or wear on the car?
No, only fuel. Official mileage rates for business travel, like the IRS standard mileage rate or HMRC's approved mileage allowance, are meant to cover more than fuel, which is why they're higher than fuel cost alone.