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Car insurance: Petrol vs Diesel

Should I get a petrol or a diesel car?

published: 03 September 2021
Read time: 5 minutes

There are many differences between petrol and diesel cars – but the choice you make could end up saving you money, even on your insurance

Petrol vs diesel cars: which should I buy?

New petrol and diesel cars will only be available in UK car showrooms until 2030, the government has said. And new hybrid cars are also to be phased out by 2035. 

If you want to drive a brand-new car, you’ll therefore have to go fully electric after that point.

New and used petrol and diesel cars are still available at the moment, though. So if you’re not yet ready to join the electric revolution, should you go for a petrol engine or a diesel engine? Or is it time to try a hybrid? 

Our guide to the pros and cons of each, including how much they cost to insure, will help you make the right choice.

Which cars are cheaper to buy?

Diesel cars are generally more expensive than petrol cars. You can expect to pay about £1,500 more for the same make and model family car if you want a diesel engine rather than a petrol one. 

However, with diesel vehicles getting a bad press of late, you may be able to secure a hefty discount on a diesel car if you’re willing to negotiate with the dealer. 

Hybrid and electric models, meanwhile, usually cost more than similar specification petrol or diesel cars. Perhaps that’s why only 0.6% of insurance quote requests via MoneySuperMarket are currently for electric vehicles. 

Which cars are cheaper to fuel and maintain?

Diesel is slightly more expensive than petrol in the UK. But motorists who drive a lot, especially over long distances, tend to prefer diesel to petrol anyway because diesel cars remain more economical due to their lower fuel consumption. 

On the flipside, many newer diesel cars have fancy filters and emission-busting systems, which can mean they cost more to repair than their petrol counterparts.

So when making your choice it’s worth considering how much you really drive each year. Figures indicate the average UK motorist now travels under 8,000 miles a year, which suggests most of us would be better off with a petrol rather than a car.

Which cars are cheaper to insure? 

The type of car you have is just one of the factors insurers take into account when setting your premiums. And its engine size and value are likely to have more impact than the type of fuel it uses. 

However, as the cost of repair and replacement parts is often higher for diesel cars, you may pay slightly more to drive a vehicle with a diesel engine.

Engine Type


Average annual premiums










Based on fully comprehensive policies with one driver holding a fully UK driver's licence. MoneySuperMarket data collected between January and June 2021, accurate as of August 2021.

Which cars are cheaper to tax?

Diesel cars used to be favoured with low tax rates because they had relatively low CO2 emissions. Now, however, they are known to produce high levels of Nitrogen Oxide (NOx), as well as tiny soot particulates that can enter the lungs and cause asthma attacks. 

If you drive an older diesel-fuelled car, you are likely to have to pay much higher tax on it as a result. And we may well see even higher taxes introduced for diesel cars over the next few years. 

Which cars are greener? 

All cars with combustion engines – including hybrid models – produce Nitrogen Oxide (NOx). But generally speaking, diesel cars are the worst offenders, producing around eight times as much NOx as their petrol-powered equivalents. 

girl relaxing in car passenger seat

What is E10 petrol?

E10 petrol contains up to 10% renewable ethanol, which should help to reduce the CO2 emissions produced by petrol cars. It’s currently being phased in as the standard (95 octane) petrol grade in the UK, taking over from E5 petrol that contains up to 5% renewable ethanol.

Already widely used in other parts of the world, E10 petrol can be used in all petrol-fuelled cars manufactured since 2011, making it compatible with 95% of petrol cars on the road in the UK, according to government figures. E5 petrol will remain available for motorists with petrol cars that cannot use E10 petrol. 

Electric and hybrid cars: the future?

Whatever your view of hybrid and electric cars, with government rules forcing car manufacturers to phase out diesel and petrol models by 2030, it won’t be long before they start to make up the majority of the vehicles on UK roads. 

Are electric and hybrid cars cheaper to buy?

No, hybrid and electric vehicles are usually more expensive than petrol or diesel cars. A new entry-level Nissan Leaf, for example, will set you back about £26,000. That’s around £4,000 more than a new Ford Focus with similar specifications.

Are they easier and cheaper to maintain?

Electric cars should prove cheaper to run, especially if you charge the up overnight. They are also a lot cheaper from a tax point of view; there is no road tax to pay on electric cars that produce no exhaust emissions.

Hybrid cars are also cheaper to tax that petrol or diesel vehicles. How economical they are to run depends on the type of hybrid you choose – plug-in or self-charging – and how you use it. They tend to work out cheaper over shorter journeys, but can prove more expensive if you often go on long, high-speed journeys. 

Are they cheaper to insure?

As with petrol and diesel cars, insurance costs for hybrid and electric models depend on a range of factors, including your age and driving history.

Electric cars tend to be in higher insurance groups because they can cost more to repair after an accident, making them more expensive to insure.

However, as hybrid cars become more popular, insurance quotes for these cars are becoming more competitive.

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