Real-world MPG: convertibles that beat 40mpg

  • Six drop-tops achieve more than 40mpg in our tests
  • Only two are diesels; one petrol beats 45mpg
  • Results indicate real-world fuel economy
Words ByEd Callow

Need a valuation?

Obtain a FREE used car valuation for any vehicle.


An article image
An article image

What Car?’s technicians drive new cars every week to bring you True MPG fuel economy data. Unlike official Government figures generated by a laboratory test, the numbers we publish are gained from real-world conditions.

This week we’re looking at the most economical convertibles that we’ve tested so far. Most have petrol engines and manual gearboxes, and all beat 40mpg in our test.

1. Vauxhall Cascada 2.0 CDTi – official 54.3mpg: True MPG 47.4mpg

The Cascada lacks the dynamic poise of some of its rivals, but it’s still a comfortable four-seat drop-top that’s quiet and spacious enough for everyday use. This 2.0-litre diesel offers a decent blend of affordability, running costs and potential resale value.

2. Citroen DS3 Cabriolet 1.6 DStyle – official 49.6mpg: True MPG 45.2mpg

The DS3 doesn’t handle or ride as well as a convertible Mini, but it’s not a bad buy. The cabin is classy and practical compared with rivals, and the engines are strong. The range-topping 154bhp DSport is our pick.

3. Mercedes E350 CDI Cabriolet – official 41.0mpg: True MPG 43.7mpg

Unlike some cars in this list, the E-Class Cabriolet isn’t designed to get you anywhere in a hurry. It’s a well-equipped car, though, with a clever system that means passengers in the back will arrive as unruffled as those in the front. We tested this engine before a face-lift, but it should still be just as efficient.

4. Fiat 500C Abarth – official 43.5mpg: True MPG 42.2mpg

This is an unashamedly retro car that’s brimming with character and is decent to drive; in fact, this 138bhp petrol gives it genuine hot hatch pace. It won’t cost the earth to run, but the ride and visibility are disappointing. Don’t be tempted by the on-paper efficiency of the Twinair engine, though; our tests show it will drink more fuel than this Abarth version.

5. Mini Roadster 1.6 Cooper S – official 47.1mpg: True MPG 40.8mpg

The Mini Roadster is our reigning Open Top Car of the Year. If you’re after a desirable and affordable drop-top, and don’t need more than two seats, it should be on your list; probably at the top.

6. Audi TT Roadster 1.8 TFSI – official 43.5mpg: True MPG 40.7mpg

This is another winner in our 2013 Car of the Year Awards – we think it’s the best open-top car you can buy at its price point. It’s a proper soft-top sports car that’s fantastic to drive and affordable to own. If you can spend a bit extra, get the 208bhp 2.0 TFSI version.

More new models are added to our True MPG database every week. Visit to see the full range of cars we’ve tested, and find out what you really can expect to achieve on UK roads.