Petrol vs diesel cars

When it comes to buying a car, one of the biggest decisions is whether to buy diesel or petrol. We weigh up the pros and cons of each to help you decide which fuel type will work best for you.

Julie Daniels

Motor insurance expert

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Last Updated 5 SEPTEMBER 2022

Should I get a diesel or petrol car?

When you’re comparing the merits of diesel and petrol, there’s a few things to think about, including how much you want to spend, your mileage and where you drive your car.

Are diesel or petrol cars cheaper to run?

Diesel cars tend to be more expensive to buy than petrol cars, and diesel fuel is slightly more expensive. But if you use the motorway frequently and clock up a lot of miles in a year, a diesel car has better fuel consumption and so is likely to be more economical.

However, it’s worth bearing in mind that the average UK driver now travels less than 7,000 miles a year, so you may well find it’s not worth the extra outlay.

Are diesel or petrol cars better for the environment?

Diesel cars were initially welcomed for reducing carbon emissions. But they were found to produce higher levels of particulates – tiny bits of soot that enter the lungs and lead to asthma attacks.

Experts estimate that between 28,000 and 36,000 people die every year as a result of air pollution in the UK, and diesel cars are thought to be a big part of the problem.

Are there restrictions on diesel cars?

To combat air pollution, major cities, including London and Birmingham, have placed restrictions on older diesel cars in central areas, with a daily surcharge for driving them. Newer diesel cars manufactured to the Euro 6 standard don’t have to pay the charges, but cars registered before September 2015 are likely to be subject to them.

Will I pay more in tax for a diesel or petrol car?

The road tax you pay will depend on whether your car meets the government’s Real Driving Emissions 2 (RDE2) standards, which set the maximum level of car NOx (nitrogen oxide) emissions for a vehicle.

When you first register your vehicle, you’ll pay an up-front tax rate based on the vehicle’s CO2 emissions to cover you for 12 months. This will be more expensive for cars that don’t meet the RDE2 standard. You can ask your car manufacturer what the base emissions are for your vehicle.

After the first year, you’ll need to pay vehicle tax every 6 or 12 months at a different rate, depending on your fuel type. This price is the same for petrol and diesel vehicles, but lower for vehicles using alternative fuels.

You don’t have to pay road tax on electric cars.

Will having a diesel or petrol car affect my car insurance?

That’s not so clear cut. The cost of your premium depends on a number of factors, not just what type of car you have. Insurance providers will take into account:

your age
where you live
how long you’ve been driving
how many miles you drive each year
whether you have any driving convictions
whether you have a no-claims bonus (and if so, how many years’ worth)

When it comes to assessing your car, other factors also impact your car insurance, such as its age, value, security, and any modifications. Your insurance provider will also consider the cost of repair and replacement parts. Many newer diesel cars have fancy filters and emission-busting systems, which can make them more expensive to repair than their petrol counterparts. This could lead to higher insurance premiums.