Fuel Cost Calculator
Work out the fuel needed and total cost for any trip.
How to use the Fuel Cost Calculator
- Enter your trip distance in kilometres.
- Enter your vehicle efficiency in km per litre.
- Enter the fuel price per litre.
- See the fuel used and total cost.
Fuel used = Distance ÷ Efficiency · Cost = Fuel used × Price
About the Fuel Cost Calculator
This works out a trip in two steps: fuel used is distance divided by efficiency, and the cost is that volume times the price per litre. It reports total cost, litres burned and cost per kilometre — the useful figure for comparing routes. The currency is whatever you type.
The trap is units. This page takes kilometres, kilometres per litre and price per litre, and fuel economy is quoted in mutually incompatible ways worldwide, so convert before you type. US mpg and imperial mpg are different measurements sharing a name — the imperial gallon is about 4.55 litres against the US gallon's 3.79, so the same car scores roughly 20% higher in imperial mpg. To reach km/L, multiply US mpg by about 0.425, or imperial mpg by about 0.354. L/100km is stranger still: it is inverted, so lower is better, and it does not scale linearly against mpg. Convert with km/L = 100 ÷ (L/100km) — so 8 L/100km is 12.5 km/L.
Treat the answer as a planning estimate, not a promise. Real consumption swings with speed, load, terrain, weather, air conditioning and driving style, and quoted factory figures are usually optimistic. For accuracy, work out your real efficiency from your own refills. For comparing pump prices see the unit price calculator; EV owners want the electricity cost calculator.
Frequently asked questions
What units does this take?
Kilometres for distance, kilometres per litre for efficiency, and price per litre. There is no mpg or L/100km input, so convert your figure first — entering mpg into the km/L box will give you a badly wrong answer rather than an error.
How do I convert mpg or L/100km to km/L?
Multiply US mpg by roughly 0.425, or imperial mpg by roughly 0.354. For L/100km, divide 100 by it — 6 L/100km is about 16.7 km/L. Note that L/100km is inverted: a lower number is a more efficient car.
Why do US and UK mpg figures differ for the same car?
Because the gallons differ. An imperial gallon is about 4.55 litres and a US gallon about 3.79, so the same car returns a bigger number in imperial mpg — around 20% higher — despite burning identical fuel. It is a units artefact, not a better engine.
Where do I find my real fuel efficiency?
Fill the tank, reset the trip meter, drive normally, then fill again and divide the kilometres driven by the litres it took to refill. That gives your true km/L, which is usually worse than the manufacturer's quoted figure and far better for budgeting.
How accurate is the cost?
It is exact arithmetic on the numbers you supply, but real-world consumption varies with speed, load, terrain, weather and driving style. Treat it as a budgeting estimate — motorway cruising and stop-start city traffic can differ enormously for the same car.
Guides & articles about this tool
How to Work Out the Fuel Cost of Any Road Trip
Planning a road trip? Work out the fuel cost before you leave so you don’t get caught short. You only need three things: how far you’re going, how thirsty…