Diesel journey cost
Work out the fuel cost of a diesel journey from the distance, your car's fuel economy and the price at the pump.
Result
Fuel used
Cost
How to use this calculator
- Enter the journey distance in miles.
- Enter your car's fuel economy in mpg (UK gallons).
- Enter the current diesel price per litre.
- Read the fuel used and total cost.
Assumptions
- Uses UK gallons (4.54609 litres).
- Diesel engines typically return higher mpg than equivalent petrol engines, especially on motorway journeys — use your car's actual figure.
Technical details: what the fields mean
- Journey distance
distanceMiles - Total journey distance, in miles.
- Fuel economy
mpg - Miles per UK gallon — use your car's real-world average rather than the official spec figure.
- Diesel price
pricePerLitre - Current diesel price, in pounds per litre.
Methodology
Litres used = (distance ÷ mpg) × 4.54609 (litres per UK gallon). Cost = litres used × price per litre.
Worked example
200 mile journey, 55mpg, £1.50/litre
Inputs: distanceMiles=200, mpg=55, pricePerLitre=1.50
Result: 16.5 litres, £24.80
Practical guidance
- Diesel typically shows its efficiency advantage most on long, steady motorway journeys rather than short urban trips.
- Compare to the petrol journey cost calculator using the same distance for a direct comparison.
Common mistakes
- Using a US gallon figure instead of a UK gallon.
- Assuming diesel is always cheaper per mile without checking the current diesel-vs-petrol price gap, which changes over time.
FAQs
How much does a 200 mile diesel journey cost?
At 55mpg and £1.50/litre, about £24.80.