Petrol or diesel: which is right for me?

May 2, 2016 by Joe Newman | Guides | Choose a used car

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With the controversies around the recent emissions scandal, one of the age-old questions of buying a car has again been brought to the fore: ‘Should I buy a diesel or a petrol?’

The truth is that there isn’t any right or wrong answer – it completely depends on what you’re looking for from your car. Although diesels have become increasingly popular in recent years, petrol still rules the road in the UK. We can’t get enough of the stuff. Of the nearly 29 million cars on the UK roads, only 35% are diesels.

There’s generally a conception that diesels are more fuel efficient and environmentally friendly, but don’t offer the responsive driving experience of a petrol. Before we run through the pros and cons of each, why not take our quick quiz to see which one is best for you?

Fuel Economy

Even though petrol cars are catching up, if you need to drive a lot for work, you want to be stopping at the pump as little as possible. In this case a diesel really is the best option, as it's around 30% more fuel efficient than petrol.

According to research by the Telegraph, this means that after you’ve driven 30,000 miles in your petrol car, on average you’d have spent around £500 more than had you bought a diesel. Seems like a lot doesn’t it? Although we all like to save money, the actual saving you’ll experience is just under £14 per month, so it really does depend on how you prioritise your money and how this extra cost affects your budgeting.

You should also think about the cost of each of the fuel options. In previous years, UK oil refineries have focused their production on petrol, so subsequently the cost has been lower, but more recently the trend has begun to balance out. According to the RAC, for the first time in 20 years you can now find diesel on your local forecourt for less per litre than petrol. So the cost of running a diesel is getting lower and lower all the time, meaning, in terms of fuel economy, diesel is the clear winner now and probably will be in the future.

Diesel: 1 Petrol: 0

Purchasing costs

Probably the most obvious cost you have to consider is the initial cost of the car. Petrol cars are pretty much always cheaper to buy than the diesel equivalent. As a general rule of thumb, the cheaper the car, the larger the extra outlay will be for a diesel when compared to the petrol equivalent. Consumer group 'Which?' has found that if you’re buying a diesel new the extra premium for the same spec. model will be somewhere between £1000-£2000. The difference, however, is significantly reduced if you go for a used option from a site such as Carspring. Still, however, petrol wins this one.

Diesel: 1 Petrol: 1


As well as the initial purchase price, there are lot of other costs to think about when you decide to buy your car. Additional costs such as depreciation, tax/insurance and servicing should all be considered. When buying a car, depreciation is one of those hidden costs that you may not initially consider. The Telegraph’s research has also found that of the UK’s best-selling cars, a petrol car bought new can lose up to £1000 more of its value than an equivalent diesel… Diesel definitely wins this one.

Diesel: 2 Petrol: 1


Next comes insurance… Over the last couple of decades, insurance has become our number one cost concern after the initial cost of the car. According to insurance comparison website,, diesel cars are the more expensive option on average, costing around 10-15% more. Depending on how experienced you are as a driver, this could cost you a small fortune, particularly if you've just passed your test. Petrol, therefore wins this one.

Diesel: 2 Petrol: 2


In terms of tax, diesel tends to be cheaper than the equivalent petrol because road tax is calculated on the CO2 emissions of the car. However, this saving is generally not a huge one. In reality, road tax is such a small percentage of the running costs of your car, you're not going to save a load of money in this area by choosing one or the other. Still, diesel wins.

Diesel: 3 Petrol: 2


Now comes servicing… On the face of it, with fewer services per mile, it looks like a shoe in for the diesel. However, you’ve got to also consider the cost of the service when it does occur. This is usually a fair bit higher for a diesel car than a petrol, so really it depends half on luck and half on your driving style. ­­­­­If you're prone to having your car serviced more often, or you buy a more unreliable model, you'll actually save money on servicing by opting for a petrol. If you're a conservative driver, get lucky and buy a really reliable model, you're best off opting for a diesel. Both therefore have their pros and cons, so it's too close to call - a tie here...

Diesel: 4 Petrol: 3

Congestion charge

An extra consideration, if you live in London, is how often you’ll be driving into the central Congestion Charge Zone. There are upcoming plans to charge extra for diesel cars entering the ‘Ultra Low Emission Zone’. Cars that were registered before 2006 or don’t comply with ‘Euro 6 emissions standard’ regulations will be subject to a supplementary charge. Although not confirmed, it has been suggested that this could work out as a premium of £11.50 per trip. This therefore is a win for petrol.

Diesel: 4 Petrol: 4

Driving Experience

While you’ll find many people who say that they’d never drive a diesel, it’s not often true the other way around. Come on, it’s not as if you’d catch Lewis Hamilton or Jenson Button racing around Silverstone in a diesel...

Diesel engines will usually be less powerful than a similar sized petrol engine. So they're not as fast, right? Well, no – not quite. A diesel engine gives you more torque than a petrol, which means you’ve got much more traction - perfect if you're going to be pulling a caravan or you're driving on roads with steep inclines. This is balanced by the fact that most diesels are now fitted with a turbo, which can result in a 'turbo lag' while the turbo engages, which can leave a gap in performance and pull - not what you want while you're overtaking.

A petrol engine provides a much more refined performance than the alternative, with much less vibration and noise. Also, while a petrol engine may need to be worked harder, they're also a lot quieter and smoother when reaching the higher end. Petrol engines have the further advantage of being significantly lighter than diesels, with a more poised and balanced weight distribution, which means they're inevitably more nimble in the corners.

Petrol engines remain the driver’s choice - giving you a much quieter, more refined and responsive drive. Plus, you'll get much more power than from an equivalent diesel engine with the same capacity (even if you get less torque). And, although the level of refinement and performance that diesels provide has done some catching up in recent years, there is still only one winner – petrol.

Diesel: 4 Petrol: 5


If we’re just looking at the emission of carbon dioxide, there is only one winner here. In the last decade or so, owners of diesel cars have enjoyed big tax breaks on their vehicles because of the comparatively low level of CO2 emissions when pitted against their petrol cousins. The fact that diesel cars emit less CO2 is undoubtedly a good thing, as the less CO2, the less likely we are going to experience ‘the greenhouse’ effect and subsequent global warming.

Diesel, however, although better for the ozone layer is much worse for us. This is because their engines omit much ‘dirtier’ fumes than petrol. The nitrous dioxide and ‘particulates’ (effectively soot) that diesel car exhausts produce can hang heavily in the air, significantly reducing the quality of the air. Research suggests that poor quality air is an increasingly significant factor in the number of premature deaths.

So, on this level it really depends what you value – the ozone layer or the air quality in your local town or city...

We end on a tie then...

And the winner is...

Overall, the best option really depends on what your priorities – the model you opt for, how many miles you drive a year and how likely you are to sell the car on in the future. On many levels a diesel car is a lot cheaper, particularly if you get it at a good price by using a site like Carspring. However, petrol generally wins on a lower initial cost, lower insurance premiums and lower servicing charges. Diesel, although catching, still isn’t quite at the level of a petrol when it comes to driving performance.

A slim victory for Petrol then, but whatever you end up opting for, take a look through the Carspring website for a great selection of expertly inspected used cars. It's the safe, secure and seriously easy way of buying a used car online.

Diesel: 5 Petrol: 6