Cheap runners: most (and least) fuel efficient cars 2023

A look at the cars that deliver the best fuel economy, and those that offer the worst fuel efficiency.

Being a driver is expensive.

It’s not just the initial cost of purchasing a car, the insurance premiums or trips to the garage to get things put right that can cost a small fortune.

Though most of us are driving less than we used to, the cost of constantly keeping it fueled adds up over the years.

And while finding a forecourt with competitive prices makes a difference, it’s even more important to find an efficient car.

After all, the more miles to the gallon you get, the fewer trips to fill up you need to make (and in the current environment of long queues it's a real time-saver as well).

However, you can’t always trust the miles per gallon (mpg) figures you get from the motor manufacturers.

That’s why the experts at WhatCar? put cars through real-life tests in order to calculate a True MPG measurement.

It's worth noting that there is a separate 'range' test for electric motors, so that won't appear here.

So, let’s take a look at the most efficient motors, and what they are likely to cost you.

10 ‒ Suzuki Baleno 1.0

The Suzuki Baleno was on sale between 2016 and 2019, so it's no longer available new. 

The WhatCar? reviewers call it a “small yet practical hatchback”, that is cheap to buy and run.

The WhatCar? team reckons you can pick one up for between £6,000 and £12,000 depending on mileage.

It has a True MPG of 55.2.

=7 ‒ Volkswagen Up 1.0

There are three motors sharing seventh place, each of which scored a True MPG of 56.

First there’s the Volkswagen Up, which is reportedly a solid choice if you’re in the market for a small car. According to WhatCar?, it is great on regular streets but you’ll start to feel outmatched on the motorway.

Prices start at £13,680.

=7 ‒ Seat Leon 1.6 TDI 110 Ecomotive

Also with a True MPG of 56 is this version of the Seat Leon.

It is essentially Seat’s version of the Ford Focus, and offers “tidy handling and a long list of standard equipment” according to WhatCar?. 

It’s a motor that was on the market between 2013 and 2020. You can expect to spend between £5,000 and £18,000 depending on the age and the mileage of the motor you go for.

=7 ‒ Honda Jazz 1.5 i-MMD Hybrid

And then there’s the Honda Jazz. It wins praise for its “practical interior”, including flip-up rear seats, which mean you can effectively create a second boot.

As a full hybrid you can also rely on electric power when travelling short distances.

The RRP starts at £20,720, and also has a True MPG of 56.

6 ‒ Vauxhall Astra 1.6 CDTi 110 Ecoflex

WhatCar? said it hasn’t generally been a fan of the Astra, but this generation of models has changed that. The combination of its lightweight nature, space and price are all big selling points.

You can expect to spend between £7,250 and £9,090.

This version of the Astra manages a True MPG of 56.3.

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5 ‒ Suzuki Celerio 1.0

The Celerio is another motor that is no longer on sale, having been taken off the market in 2019.

It performed well, with a decent line-up of equipment and a “pretty lively” engine in the words of WhatCar.

The Celerio achieved a True MPG of 57.8, and you can get one for between £3,500 and £9,000 depending on age and mileage.

4 ‒ Skoda Octavia 2.0 TDI 115

The Octavia is a “seriously impressive family car” according to WhatCar?, particularly if you cover a lot of miles.

It wins praise for a spacious and practical interior, as well as a “plush ride”.

It manages a True MPG of 57.9, and while this model is no longer available new, WhatCar? reckons you can get one for around £28,000.

3 ‒ Suzuki Ignis K12D 1.2 Dualjet Hybrid

Third spot goes to the Ignis, with a True MPG of 59.9.

It’s a mild hybrid, and a front-wheel drive.

You can expect to pay around £18,349 new.

2 ‒ Toyota Yaris 1.5 Hybrid

WhatCar? points out that hybrids don’t come cheaper than the latest Yaris, while it is also kind on the bank balance when it comes to running costs.

It also suggested that the car is “easy to recommend”.

It has a True MPG of 59.93, and an RRP of £23,919.

1 ‒ Toyota Yaris Cross 1.5 Hybrid

Top spot goes to another Yaris, this time the Cross 1.5 Hybrid, with a True MPG of 60.1.

It boasts the combo of small SUV styling and a bigger battery which means its electric power can take it further than the hatchback Yaris.

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The least efficient cars

What about the other end of the spectrum, the cars that deliver the most disappointing True MPG under WhatCar’s testing?

Here are the worst performers: