True MPG: most and least efficient cars revealed

What Car?'s laboratory tests use a real-world driving route to show what fuel economy you can really expect. So, what are the best and worst performing cars?...

True MPG - Mercedes GLE emissions test

What Car?’s True MPG real-world fuel economy figures show what sort of efficiency you can really expect from a car.

Tests are conducted in a laboratory under tightly controlled conditions to ensure repeatability within 1%, but they are based on a real-world route that takes in town, rural and motorway driving.

The results reflect what's achievable if you’re driving gently and sticking to speed limits, but aren’t resorting to any unrealistically slow acceleration or special 'hypermiling' techniques.

As a result, True MPG is not only fully reflective of real-world performance, but much more realistic than the official government fuel economy figures that car manufacturers have to quote.

Below we count down the top 10 performers – and reveal the 10 cars that used the most fuel.

The 10 most fuel-efficient cars tested:

10.  Suzuki Baleno 1.0

2016 Suzuki Baleno 1.0 Boosterjet review

True MPG 55.2mpg

The Baleno is a small yet practical hatchback which will also cost you a pittance to run. It was discontinued in 2019, but there are plenty of examples on the used market.

New Volkswagen Up vs Hyundai i10 vs Renault Twingo

True MPG 55.9mpg

It's been around for a while, but the Up remains a solid choice if you're in the market for a small car, thanks to its smart interior and fun handling. This 1.0-litre petrol engine may only have 59bhp, but that means it has enough pep for city streets. You'll quickly feel out-matched on the motorway, though.

Read our full Volkswagen Up review >>

=7 Seat Leon 1.6 TDI 110 Ecomotive

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2019 Seat Leon front

True MPG 56.0mpg

The Leon is Seat's answer to the Ford Focus and Vauxhall Astra, and in addition to good real-world fuel economy, offers tidy handling and a long list of standard equipment. Just make sure you can live with its rather firm ride. The Leon has since been updated, but some of its engines remain very economical. 

Read our full Seat Leon review >>

=7 Honda Jazz 1.5 i-MMD Hybrid

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Honda Jazz 2022 front right tracking

True MPG 56.0mpg

The Jazz's party piece is its practical interior, which includes cinema-style flip-up rear seats, allowing you to take long loads on the rear bench. Elsewhere, it switches between petrol and electric power very well, and even handles sweetly. It's not the last word in refinement, though, and costs more than many rivals.

Read our full Honda Jazz review >>

6. Vauxhall Astra 1.6 CDTi 110 Ecoflex

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How to buy your perfect Vauxhall Astra

True MPG 56.3mpg

In the past, we haven't rated the Vauxhall Astra particularly highly, but in its latest form the car is much more impressive. It has a lightweight construction which aids efficiency, plus, it's spacious and well priced.

2018 Suzuki Celerio 1.0 SZ4 auto

True MPG 57.8mpg

Despite being one of the cheapest new cars around until it was taken off sale in 2019, the Celerio came with a decent array of equipment, including air conditioning, a DAB radio and Bluetooth connectivity. The only engine option was a pretty lively and extremely frugal 1.0-litre.

Read our full used Suzuki Celerio review >>

4. Skoda Octavia 2.0 TDI 115

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Skoda Octavia 2021 nose

True MPG 57.9mpg

If you cover enough annual miles to justify having a diesel engine, then this 2.0-litre unit in the Skoda Octavia will save you a bundle on running costs. The Octavia is a seriously impressive family car in other respects, too, with a spacious and practical interior and a plush ride.

Read our full used Skoda Octavia review >>

3. Suzuki Ignis K12D Dualjet Hybrid

Save money on a new Suzuki Ignis with What Car? >>

Suzuki Ignis 2021 front cornering

True MPG 59.9mpg

This version of the Ignis SUV is a mild hybrid, which means a small electric motor works alongside its 1.2-litre petrol engine, helping to get you moving and reducing the strain on the engine. It's front-wheel drive, but even if you decide four-wheel drive is a must, the average True MPG only drops to 53.3mpg.

Read our full Suzuki Ignis review >>

2. Toyota Yaris 1.5 Hybrid

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Toyota Yaris 2021 front

Test MPG  59.93mpg

Hybrid cars don't come any cheaper than the latest Yaris, yet it's also exceptionally frugal. Add in that it's well priced and offers perky performance, and it's easy to recommend. There are plenty of rivals which offer more space, though. It's also well priced and offers perky performance, although there are plenty of small cars that are more spacious.

Toyota Yaris Cross 2022 front right tracking

True MPG 60.1mpg

Take the Yaris' ultra-efficient 1.5-litre petrol engine and electric motor, add chunky SUV styling and a raised ride height and, hey presto, you've created the Yaris Cross small SUV. Even better, the Yaris Cross is slightly more efficient than its hatchback sibling, and has the best average fuel economy figure of any car we've put through our True MPG test

Read our full Toyota Yaris Cross review >>

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