Petrol Vs Diesel Lifetime Cost Calculator
Calculate the true lifetime cost of owning a petrol vs diesel car in the UK. Compare fuel costs, MPG, and initial premiums to see which is cheaper over time.
Vehicle & Ownership Details
Enter your driving habits and fuel costs to compare petrol vs diesel over time
How many miles do you drive in an average year?
How long do you plan to keep the car?
Current average price of petrol in pence per litre.
Current average price of diesel in pence per litre.
Real-world miles per gallon for the petrol car.
Real-world miles per gallon for the diesel car.
How much more does the diesel car cost to buy upfront? (Enter 0 if same price).
Lifetime Cost Comparison
Total ownership costs for petrol vs diesel
Enter your vehicle and ownership details above, then click Calculate Lifetime Cost to see which fuel type is cheaper.
UK Fuel & MPG Statistics
Understanding average fuel costs and efficiency helps you set realistic expectations for your car ownership budget.
| UK Metric | Statistic | Context / Details |
|---|---|---|
| Average Petrol MPG | 45 – 50 MPG | Real-world average for modern hatchbacks |
| Average Diesel MPG | 55 – 65 MPG | Real-world average, better for motorway |
| Average Petrol Price | ~140p / litre | Varies by supermarket vs motorway |
| Average Diesel Price | ~145p / litre | Often slightly higher than petrol |
| Break-even Mileage | 12,000+ / year | Point where diesel fuel savings offset premium |
Petrol Vs Diesel FAQ
Everything you need to know about choosing between petrol and diesel, fuel costs, and UK driving conditions.
Yes, but generally only if you drive high annual mileages (typically over 12,000 to 15,000 miles) and do a lot of motorway driving. For lower mileages or mostly city driving, a petrol or hybrid car is usually more cost-effective and avoids potential DPF (Diesel Particulate Filter) issues.
To calculate the lifetime cost, add the initial purchase price to the total fuel cost over the years you plan to own it. Total fuel cost is calculated by dividing your annual mileage by the car’s MPG, converting gallons to litres (multiplying by 4.546), and multiplying by the fuel price per litre, then multiplying by the number of years.
The average real-world fuel economy for a petrol car in the UK is around 45-50 MPG, while diesel cars typically achieve 55-65 MPG. However, official WLTP figures are often higher than real-world driving conditions, so it’s best to use conservative estimates for budgeting.
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