Driver tools Petrol and diesel fuel costs

Petrol or diesel?


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Example running costs comparing a petrol with a diesel car
Example numberCar price differenceAnnual fuel cost petrolAnnual fuel cost dieselAnnual CO2 emissions petrolAnnual CO2 emissions dieselNo. of years to recoup diesel price premium

Choosing between a petrol and a diesel car can be difficult. While you can be fairly confident the petrol model will be cheaper to buy, knowing which is going to cost you more in the long run is a bit more difficult.

This is because the overall running costs of petrol and diesel cars are affected by so many factors, including fuel prices, servicing bills and emissions-based charges. 

We have our own fuel efficiency test to give more realistic mpg figures - these are available in all our car reviews

The calculator on the right only takes initial purchase price, fuel costs and mileage into account, but should give you an idea of how many years’ driving it will take to make buying a diesel the most cost-effective choice - if indeed the diesel will ever be cheaper.

The 'diesel payback' period could take much longer than you would think - especially for lower mileage drivers. However, if the diesel car saves you money on car tax and depreciation, it may pay for itself sooner.

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Other sections in this guide

  1. Overview
  2. Petrol and diesel fuel costs
  3. Choosing between petrol and diesel
  4. How to drive more efficiently