Petrol or Diesel: Which Car Is Cheaper to Own?

What’s cheaper to own, a petrol or a diesel car? Diesel cars are usually more efficient for long-distance drivers, while petrol cars are cheaper upfront and simpler to maintain. This guide helps you choose based on costs, performance, and future rules.

Our aim is to cut through the confusion, giving you all the info you need to make an informed, confident decision. We’ll look at factors such as annual mileage, journey type, future rules around petrol and diesel cars and much more. Let’s settle the whole petrol vs diesel debate once and for all!

Petrol vs diesel: key takeaways 

• Petrol cars cost less to buy new and generally have lower maintenance costs than a diesel car
• Diesel cars give better fuel economy and are better for towing and motorway cruising
• Petrol cars emit fewer particulates; diesels emit less CO2
• Diesel can be ideal for rural or high-mileage drivers; petrol suits low-mileage and city use
• Sales of new petrol and diesel cars will end in 2030, but hybrids will continue until 2035
• Hybrids or electric cars may offer better value depending on your needs

Comparing the running costs

Purchase price and depreciation

Diesel cars usually cost more to buy new, but they depreciate faster than petrol cars. That’s because diesel engines are more complex and cost more to produce. Like-for-like, prices for diesel cars are about 5% higher. For example, a new VW Golf diesel costs about £1795 more than the petrol version. 

That means used diesel models can be cheaper than petrol cars. However, that difference often vanishes on the used market.

If you’re buying a used car, you’ll find prices for petrol and diesel models are generally similar, although diesel cars (especially smaller ones) will often cost less. That’s because diesel cars have become less popular in recent years, causing higher depreciation that wipes out their extra cost when new. 

There are exceptions, though. Some cars, such as big 4x4s and models popular as tow cars, are more desirable with a diesel engine. So you may find that a larger used car with a diesel engine costs more than an equivalent petrol model. 

Fuel costs and efficiency (MPG)

Diesel cars are more fuel-efficient than petrol, making them cheaper to run if you cover high mileage. Diesel engines work at higher compression, and the fuel is more energy-dense, which explains the efficiency gain.

Using the VW Golf as an example, the petrol averages 53mpg, while the diesel returns 65mpg. That means covering 10,000 miles uses 188.7 gallons of petrol and 153.8 gallons of diesel.

As of October 2025, diesel averages £1.42 per litre (£6.46/gal) and petrol £1.34 per litre (£6.09/gal). So, fuelling the petrol Golf for 10,000 miles costs around £1,149, while the diesel comes in at £994, a £154 saving.

However, because diesels cost more to buy new, you’d need to drive over 100,000 miles to break even. On the used car market, where diesel and petrol prices may be similar, the breakeven point could be much shorter or irrelevant.

Tax, insurance, and maintenance

Diesel cars usually cost more to insure and maintain, mainly due to their complex parts like diesel particulate filters (DPFs), which can be expensive to repair if clogged. Petrol cars are simpler and cheaper to maintain, but the difference in road tax is generally minor.

Road tax (officially Vehicle Excise Duty or VED) depends on CO2 emissions. New cars include the first year's tax in the price, which can range from £10 to £5,490 depending on emissions. For example, our VW Golf petrol and diesel both cost £440 in year one. From year two, it’s a flat £195 per year for all post-April 2017 cars.

Used cars registered between March 2001 and April 2017 are taxed on a CO2 scale from £20 to £760 annually. In our 2016 Golf example, the diesel costs £20 per year in tax, versus £35 for the petrol.

While maintenance costs are typically higher for diesels, overall reliability depends more on how well the car’s been looked after than on fuel type.

Driving performance and experience

Power, torque, and towing ability

Diesel cars produce more torque, making them better for towing and smoother on motorways. You’ll need fewer gear changes at low revs, which makes long-distance cruising easier. The extra torque also increases towing capacity, thanks to the engine’s weight and pulling power.

Petrol cars deliver quicker acceleration and suit city driving. For instance, the VW Golf petrol and diesel both have 113bhp, but the diesel has 221lb ft of torque compared to the petrol’s 162lb ft. The diesel hits 0–62mph in 10.2 seconds, while the petrol is slightly quicker at 9.9 seconds. Both have a top speed of 126mph.

Engine noise and refinement

In general, diesel cars are noisier than petrol models because their engines compress fuel and air at a higher pressure than petrol engines, creating a louder and harsher sound. You might also feel a bit more vibration in a diesel car if you accelerate hard. 

Newer diesel cars are quieter than older ones, however, and the increased soundproofing in more modern cars means that you might not hear much difference between a petrol and diesel car when you’re driving. From the outside, though, it’s generally hard to mistake which fuel a car uses.

Environmental impact and emissions explained

Diesel Particulate Filters (DPF) and AdBlue

The bad news is that, in the long run, both petrol and diesel cars probably aren't as good for the environment as electric cars. That's because both petrol and diesel engines burn fuel and create exhaust emissions. 

Petrol engines emit more carbon dioxide (CO2), which is known as a ‘greenhouse gas’ because it contributes towards climate change. Diesel engines, on the other hand, emit more nitrogen dioxide (NOx) and particulates, which are linked to local air pollution that can cause health issues such as respiratory diseases and lung cancer. So a diesel car may be better for the planet on a global level, but worse at a local level. 

Increasingly strict regulations mean that car manufacturers have worked hard to reduce the emissions of both petrol and diesel cars over recent years. All new diesel cars sold since 2009 have a diesel particulate filter (DPF) that reduces particulate emissions. Most diesel cars built since 2015 also have an additional system that injects a liquid called AdBlue into the exhaust system to reduce NOx emissions. These systems need to be topped up with AdBlue regularly. It’s no more taxing than filling up with screen wash and on average you’ll only need to do it every 6000 miles or so. It’s not expensive, with £20 worth likely to be good for 10,000 miles or so. 

ULEZ, Clean Air Zones, and the 2030 ban

Across the UK, some areas now charge drivers to enter if their car doesn’t meet certain emissions standards. These include Clean Air Zones (CAZs) and London’s Ultra Low Emission Zone (ULEZ), which operate independently but share the same goal: cutting urban air pollution.

To avoid daily charges, petrol cars must meet Euro 4 emissions standards (usually built after 2006), and diesel cars must meet Euro 6 (typically from 2015 onward). Most cars under ten years old will qualify.

ULEZ applies to Greater London, while CAZs are in force in places like Birmingham, Bristol, and Sheffield. If you’re unsure whether your car qualifies, free online checkers are available for UK zones, Scottish zones and ULEZ.  

Looking ahead, the UK will stop selling new petrol and diesel cars in 2030, with hybrids allowed until 2035. After that, only new electric cars will be sold. However, used petrol, diesel and hybrid cars will still be legal to buy and drive.

Pros and cons of petrol cars

Here’s a quick recap of the advantages and disadvantages of petrol cars:

Pros

• Cost less to buy new
• Generally cheaper to maintain
• Quieter to drive

Cons

• Not as fuel-efficient as diesels
• Higher CO2 emissions
• Not as suited to towing as diesel

Pros and cons of diesel cars

Here’s a quick recap of the advantages and disadvantages of diesel cars:

Pros

• More fuel-efficient
• Better for towing and motorway cruising
• Lower CO2 emissions

Cons

• Higher cost when new
• Noisier than a petrol model
• Maintenance costs likely to be higher

Alternatives to consider: Hybrid, PHEV, and EV

Hybrids vs petrol and diesel

Full-hybrid cars combine a petrol engine with an electric motor. They offer better fuel economy than petrol-only cars, especially in city driving. They’re more expensive upfront but don’t need charging.

Plug-in hybrids vs petrol and diesel

Plug-in hybrids can drive on electric power alone for 30–80 miles. They’re great for short commutes if you can charge at home or work. Without charging, they’re less efficient than hybrids or diesels.

Electric cars vs petrol and diesel

EVs offer the lowest running costs if charged at home, and newer models can travel up to 300 miles on a charge. Prices have dropped, making some EVs cheaper than petrol or diesel used cars.

Petrol, diesel, or hybrid: which is right for you?

Working out whether your next car should be a petrol, diesel, hybrid or electric model depends on a wide range of factors, including your annual mileage, financial considerations, lifestyle and any personal preferences. 

We’ve put together a cheat sheet to help you make the right decision:

Buying used: checks for petrol and diesel

When buying a used petrol or diesel car, a few simple checks can help you avoid costly surprises. First, find out whether the car uses a timing belt or a timing chain. If it has a belt, check there’s proof it’s been replaced according to the manufacturer’s schedule; failure can cause major engine damage.

Diesel buyers should also check the diesel particulate filter (DPF), which is standard on all diesels from 2009. Excessive soot on the exhaust, warning lights, or black smoke on a test drive could point to DPF issues. This is especially if the car’s mostly done short trips.

Regardless of fuel type, always check the MOT history on gov.uk to spot any past failures or patterns. Confirm that the mileage on the listing matches MOT records and take the car for a solid test drive. Listen for odd noises, check how it handles, and ask questions. A little extra homework now can save a lot later.

For more information, have a look at our used car buying checklist video.

Car finance and budget planning

Before committing to a petrol or diesel car, it’s worth working out your next car budget to check long-term affordability. Factor in all the usual suspects: fuel, tax, insurance, maintenance, and any finance repayments. Even rough estimates can help you avoid surprises later.

Diesels typically cost less to fuel over time, but they can cost more to insure and maintain. Petrol cars may be simpler to look after, but you’ll usually pay more at the pump. Maintenance is hard to predict, but choosing a car with a good reliability record helps. Independent surveys like What Car? and Driver Power are great places to start.

It’s also worth checking if fixed-price service plans are available, or budgeting for common costs like timing belt replacement or DPF cleaning. And if you’re planning to finance your car, tools like a car finance calculator and pre-approval checks can help you set a realistic budget and feel more confident about your purchase.