True MPG: most efficient executive and luxury cars

What Car?'s True MPG tests show what fuel economy you can really expect from a car. Here, we reveal the best and worst-performing executive and luxury cars we've tested...

Most efficient executive cars - True MPG

The miles per gallon (MPG) figures published in sales brochures can tempt you into buying a particular car, but those results are often misleading. Fortunately, What Car?'s True MPG tests reveal what sort of fuel economy you can expect in the real world.

To ensure accuracy and repeatability, we use strictly controlled laboratory conditions, but the tests 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.

Here we reveal the 10 most efficient executive and luxury cars we've tested so far – plus the one that used the most fuel.

The 10 most fuel efficient executive and luxury cars:

10. Mercedes-Benz E-Class E220d

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Mercedes-Benz E-Class

True MPG 44.8mpg

The E-Class offers a comfortable ride and a plush interior, plus this diesel version's comparatively low CO2 emissions and P11D value mean it's the one that makes most sense for company car drivers.

Volkswagen Passat Saloon 2019 front tracking

True MPG 45.4mpg

It can be a little gruff, but Volkswagen's latest 2.0-litre diesel engine otherwise impresses, pulling strongly across a wide rev range and delivering good real-world fuel economy.

Read our full Volkswagen Passat review >>

8. Alfa Romeo Giulia 2.2D 180

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2019 Alfa Romeo Giulia front

True MPG 45.7mpg

The 2.2-litre diesel engine in the Giulia could also be quieter, but it's even stronger and ever so slightly more efficient, while the Giulia itself is the best mainstream Alfa Romeo for years.

Read our full Alfa Romeo Giulia review >>

7. BMW 3 Series 320d

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BMW 3 Series 320d front

True MPG 47.2mpg

It may be only seventh on this list, but the 320d is our reigning Executive Car of the Year, because it's fantastic to drive, it's very affordable as a company car and it has the most user-friendly infotainment system around.

Mazda 6

True MPG 47.3mpg

While it's not as good an all-rounder as the very best executive saloons, the recently facelifted Mazda 6 has a strong but quiet diesel engine and comes very well equipped.

Read our full Mazda 6 review >>

5. Skoda Superb 1.6 TDI 120

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True MPG: best executive and luxury cars 2018

True MPG 47.5mpg

If you're after something that combines limousine-like interior space with low running costs, the Skoda Superb 1.6 TDI should be at the top of your shortlist.

Read our full Skoda Superb review >>

4. Audi A4 2.0 TDI 190

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Audi A4 35 TDI SE S tronic

True MPG 47.8mpg

A former What Car? Car of the Year, the A4 has since been beaten by the BMW 3 Series but remains a five-star car and will go slightly farther on a gallon of diesel.

Read our full Audi A4 review >>

3. Vauxhall Insignia Grand Sport 1.6 CDTi 110

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New Vauxhall Insignia Grand Sport 2017 review

True MPG 50.2mpg

The bottom step on the podium goes to this 1.6-litre diesel model. Just bear in mind that you have to put up with quite a lot of road noise in all Insignia Grand Sports and rear head room is tight.

Read our full Vauxhall Insignia Grand Sport review >>

2. Vauxhall Insignia Grand Sport 1.6 CDTi 136

Used Vauxhall Insignia Grand Sport 2017-present

True MPG 51.8mpg

In official tests, the CDTi 136 version of the Insignia Grand Sport averages 2.8mpg less than the CDTi 110, but our True MPG figures show that the tables are turned in real-world conditions.

1. Ford Mondeo 1.5 TDCi 120

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Ford Mondeo hatchback front

True MPG 53.7mpg

In addition to being the most fuel efficient executive car we've tested to date, Ford's fleet favourite is a spacious and comfortable choice with tidy handling.

Read our full Ford Mondeo review >>

And the least fuel efficient executive or luxury car...

Mercedes-Benz S-Class

True MPG 26.9mpg

The S-Class has long been one of the best luxury saloons around and is extremely relaxing to drive or be driven in. However, despite featuring mild hybrid technology, the S500 version is anything but frugal.

Read our full Mercedes S-Class review >>

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