Petrol vs Diesel vs Electric – Which Car Offers the Best Economy?


Choosing between a diesel, petrol or electric car will come down to a number of factors. There has been a long-standing battle between petrol and diesel over the decades, but the improvement of electronic technology in recent years has seen EVs have a serious stake in the conversation.


Petrol has been one of the main fuel types for well over a century and remains the most popular option for millions of drivers in the UK.

While traditionally it has lagged behind diesel in terms of fuel economy, that has changed in recent years, with a number of models now not too far off diesel cars when it comes to miles per gallon.

Petrol is a good option for drivers who do not clock up a lot of miles each year, with anyone travelling less than the average 10,000 miles probably benefiting more from using a petrol car. If it will mostly be used for low-speed journeys in and out of town, then petrol definitely makes the most sense economy wise.

The arrival of a new generation of petrol engines in recent years has seen some cars close the gap in terms of fuel efficiency. 1-litre engines placed into the likes of the Ford Focus and Ford Fiesta, or the 1.5-litre engine in Mini Hatchback, have more rev capacity and a sportier feel, along with good fuel economy that is close to those found in some diesels.

Good efficient petrol small cars include the likes of the Audi A1 (official figure 67.3mpg) and Peugeot 208 (67.3mpg). Family cars like the Peugeot 308 (70.6mpg) and Vauxhall Astra (64.2mpg) are worth looking at, while crossovers and SUVs such as the Peugeot 308 (55.4mpg) and Seat Ateca (54.3mpg) deliver efficiency.


When it comes to striking a good balance between low fuel consumption and good performance levels then diesel is still a good option.

As stated by the Society of Motor Manufacturers and Traders (SMMT), on average, diesel cars use as much as 20% less fuel than their petrol relations. Drivers of diesels also travel 60% more miles, which results in lower fuel costs in the long run.

While diesel is more expensive per litre than unleaded petrol, the average fuel economy of most engines tend to make up for over time, usually saving drivers a few hundred pounds per 10,000 miles.

Of course, diesel cars also get a bad reputation for their toxic emissions, so this is something to take into consideration when looking for a new car. Although, there have been some tests carried out by the likes of Which? that show some diesel cars emit less NOx than the average petrol car.

And if you need the vehicle for towing at any point, diesel cars are usually the go-to choice due to their pulling power, but there are some good petrol alternatives available.

Some of the most efficient diesel cars currently on the market include the Kia Ceed 1.6 CRDi (Official figure 72.4mpg), the Citroen C4 Cactus 1.6 (70.6mpg), the Vauxhall Corsa 1.3 CDTI (78.5mpg) and the Renault Clio 1.5 dCi (70.6mpg)


Electric cars are powered by an electric motor to keep it on the move, usually allowing somewhere between 80-250 miles of driving range per full charge. When you take into consideration the average commute time to work in England and Wales is 9.32 miles then this should offer coverage for most basic needs.

From 2032 drivers will no longer be able to purchase new diesel and petrol electric vehicles, which is only just over a decade away, so EVs are coming to the fore more than ever.

Fuel economy in an electric car is measured by the amount of KWh (kilowatt-hour) or Wh (watt-hour) used per set distance (usually a km or mile). For example, a Volkswagen e-Up offers fuel economy of 117 Wh/km, while a BMW i3 delivers 131 Wh/km. Usually the numbers provided by manufacturers can be overestimated, so it may be best to slightly underestimate the distance of an electric car to prevent being left stranded with a charging point close by.

Compared to petrol and diesel cars, electric cars are generally cheaper to maintain. Some estimates suggest there are models (usually at the higher end of the market – Tesla etc.) that can offer a full charge at half the cost of 50-litre diesel tank.

Excellent fuel economy for an electric car would be somewhere in the 19-23 kWh/100 miles range, with 25-30 being average and anything higher than that not proving to be value for money.

Questions? Speak to a real person

Comparing car finance and car warranties is what we do, so you will get through to someone who can help. Call us from Monday to Friday (8am - 8pm) and Saturday to Sunday (9am - 6pm).