COMPARE TWO FUEL TYPES
Petrol vs diesel calculator
Compare annual fuel spend using the mileage you drive and realistic MPG figures for a petrol and diesel vehicle.
ANNUAL FUEL COMPARISON
Compare petrol and diesel
A FAIR COMPARISON
Price per litre is only half the story
Petrol and diesel running costs depend on both the price at the pump and how much fuel each vehicle uses. Comparing price per litre alone can be misleading if the cars have significantly different MPG.
Enter realistic MPG figures for the two vehicles you are considering, then use your own annual mileage. The result shows fuel-only annual spend and pence per mile for each option.
What this calculator does not include
Purchase price, tax, insurance, servicing, repairs, emissions-zone charges and depreciation are outside this comparison. A cheaper fuel bill does not necessarily mean a cheaper car overall.
QUESTIONS ANSWERED
Frequently asked questions
Is diesel always cheaper to run than petrol?
No. Diesel can be more efficient, but diesel fuel may cost more per litre and the vehicles themselves can have different ownership costs.
What annual mileage should I enter?
Use your realistic yearly mileage from MOT records, app tracking or your own estimate.
Should I compare official MPG figures?
Real-world MPG is better when available because official figures may not match your normal driving.
Does this compare total ownership cost?
No. It compares fuel only. Purchase price, depreciation, insurance, tax and maintenance are separate.
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