MPG (UK / Imperial)
Miles per Imperial gallon is commonly used in the UK. One Imperial gallon is approximately 4.54609 litres.
Fuel Cost Calculator
Calculate the estimated fuel cost of a journey from the distance travelled, your vehicle's fuel economy and the price of fuel. Use UK MPG, US MPG, litres per 100 km or kilometres per litre.
Calculate fuel cost
Enter the fuel price in pounds per litre.
Round trip doubles the entered one-way distance.
Estimated fuel cost
—
—
Fuel required
—
Cost per distance
—
Distance travelled
—
Equivalent economy
—
Calculation breakdown
| Entered journey distance | — |
|---|---|
| Journey type | — |
| Total distance | — |
| Entered fuel economy | — |
| Equivalent fuel consumption | — |
| Fuel required | — |
| Fuel price | — |
| Estimated fuel cost | — |
This is an estimate. Actual fuel use can change with traffic, speed, weather, vehicle load, tyre pressure, terrain and driving style.
How to calculate fuel cost
A fuel cost calculation needs three things: journey distance, fuel economy and fuel price. The calculator converts those values to a common set of units, estimates how much fuel the journey requires, then multiplies that fuel volume by the price you entered.
Using MPG: Fuel required = distance ÷ MPG when the distance and gallon units match.
Using L/100 km: Fuel required (L) = distance (km) × L/100 km ÷ 100
Fuel cost = fuel required × fuel price
Fuel economy units
MPG (US)
US miles per gallon uses the smaller US liquid gallon. One US gallon is approximately 3.78541 litres, so UK MPG and US MPG are not interchangeable.
L/100 km and km/L
Litres per 100 kilometres expresses fuel consumption directly, while kilometres per litre expresses the distance travelled for each litre of fuel.
Which fuel economy figure should you use?
For the most realistic estimate, use a fuel-economy figure that reflects the vehicle and type of journey you expect to make. This could be an average calculated from your own fuel use or a recent average shown by the vehicle's trip computer.
Manufacturer fuel-consumption figures can also be used, particularly when comparing vehicles, but actual fuel economy can differ from official test results because driving conditions, speed, weather, vehicle load and driving style vary.
Whichever figure you use, make sure the unit selected in the calculator matches the figure entered. In particular, UK MPG and US MPG use different gallon sizes.
Worked example
For a 200-mile one-way journey in a vehicle returning 40 UK MPG, the vehicle requires 5 Imperial gallons of fuel. That is about 22.73 litres. If fuel costs £1.50 per litre, the estimated journey fuel cost is about £34.10.
UK MPG and US MPG are different
The same numerical MPG figure represents different fuel consumption depending on whether it uses an Imperial or US gallon. Always choose the MPG unit that matches your vehicle's fuel-economy figure.
For authoritative measurement conversion factors, see the NIST unit conversion guidance .
Why real fuel cost may differ
Published fuel-consumption figures are useful for comparison, but real-world consumption varies. Stop-start traffic, higher speeds, cold starts, gradients, towing, vehicle load and driving style can all change the amount of fuel used. Fuel prices also vary by location and over time, so CalcAtlas asks you to enter your own current price.
For more information about official vehicle fuel-consumption figures and how they compare with real-world driving, see the Vehicle Certification Agency Fuel Consumption Guide .
Limitations
This calculator estimates fuel use and cost from the distance, fuel economy and fuel price entered. It assumes the selected fuel-economy figure applies across the entire journey.
Actual fuel consumption can vary with traffic, speed, weather, terrain, vehicle load, tyre condition, driving style and other operating conditions. Fuel prices can also change between locations and filling stations.
The calculation covers fuel cost only. It does not include other journey costs such as tolls, parking, vehicle wear, maintenance, depreciation or insurance.
Frequently asked questions
How do I calculate fuel cost for a trip?
Enter the journey distance, your vehicle's fuel economy and the price you pay for fuel. The calculator estimates the fuel required and total cost.
Can I calculate a round trip?
Yes. Select Round trip and the calculator will double the entered one-way distance.
Can I use litres per 100 km?
Yes. Select L/100 km as the fuel economy unit. You can use either miles or kilometres for the journey distance because the calculator handles the conversion.
Can I enter fuel price per gallon?
Yes. Fuel price can be entered per litre, per UK gallon or per US gallon. Choose the price unit that matches the price you enter.
Does the calculator use live fuel prices?
No. Fuel prices vary by country, region and filling station. Entering your own price keeps the estimate relevant to the journey you are planning.