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Petrol vs Diesel

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Last updated: 19/04/2021 | Estimated Reading Time: 3 minutes

When it comes to buying a new car, one of the first questions you might ask yourself to narrow down your selection is whether to go for car run on petrol or diesel.

You might be wondering what the difference is, in terms of price, longevity and performance.

Are diesel or petrol cars cheaper to insure?

Will I get more mileage from a petrol or diesel engine?

We’ll answer all of these questions and more in this helpful guide.

In This Guide:

Costs of vehicle

First off, let’s look at the outright cost of buying the vehicle.

In general, diesel cars tend to cost a little more to buy than their petrol equivalents, but they also tend to last a little longer, and so this must be taken into account when working out how to balance outright cost and overall value.

Further, diesel vehicles tend to depreciate slower than those run on petrol. Depreciation is a very big deal when it comes to working out the value of a car so this can be a deal maker for some.

Fuel efficiency and cost

Diesel cars are, on the whole, more fuel efficient than their petrol counterparts. However, diesel also costs a bit more than petrol at the pump.

This means that in order to take advantage of the fuel efficiency of a diesel vehicle, you really need to own it for quite a long time. Experts suggest that you’ll need to drive 6-10,000 miles in your diesel car in order to feel the benefits, given the higher price of the fuel to start with.

So if you don’t drive that often, or don’t think you’ll have your car for that long, going for a petrol engine might be a better idea.


Given that road tax prices are worked out on a scaling basis based on the C02 emissions of the given vehicle, the tax on a diesel car, being more fuel efficient, will generally cost a little less than the tax on a petrol car.

Servicing costs

When it comes to comparing petrol and diesel cars in terms of servicing costs, a similar situation arises to when we looked at fuel efficiency.

That is to say, diesel cars, as a general rule, don’t need to be serviced as often as petrol cars, but when they do, it tends to cost a little bit more. So again, if you’re keeping your car for under five years, it is unlikely that you’ll notice much of a difference.

Additionally, as petrol engines get more and more reliable, the difference between them and diesel engines in terms of how often they need to be repaired is gradually shrinking.

Insurance costs

Now for the crucial question: which kind of car will cost more to insure?

Experts reckon that diesel cars cost, on average, around 10-15% more than their petrol counterparts. There are various reasons for this, mainly based on the extra cost of repairs and the extra cost of replacement in the event of theft.

But this needn’t worry you if you’ve got your heart set on a diesel car. Whichever kind of engine you have, whether you want cheap car insurance for a petrol car or cheap insurance for a diesel car, we’ll help you find it.

Head over to our car insurance comparison page and we’ll help you find the perfect deal for you, at no extra cost.

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