Real-world MPG: most economical convertibles

Ten of our favourite convertibles that achieve more than 32mpg in our real-world fuel economy tests


What Car?’s technicians drive new cars every week to capture our 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 we’ve tested so far, with a What Car? rating of at least three stars out of five. If you want an impressive drop-top that should do more than 32mpg in real-world driving, these ten models should be on your shortlist.

1. BMW 2 Series Convertible 220d – official 61.4mpg: True MPG 49.6mpg

The 2 Series Convertible is one of the best cars in its class, it's only narrowly beaten by the Audi A3 Cabriolet. However, when it comes to real-world fuel economy, the BMW has the edge. In our real-world tests the 2 Series Convertible returns an impressive 49.6mpg making it the most economical convertible we've tested.

2. BMW 4 Series Convertible 420d – official 55.4mpg: True MPG 49.4mpg

The 4 Series Convertible delivers pretty much all that could be asked of it. It's refined enough with the roof up to be an everyday tool, yet stylish and accomplished enough with it down to be a relaxed, sophisticated cruiser. It also returns nearly 50mpg, just 6mpg off its official figure.

3. Mercedes-Benz E-Class Cabriolet E220 CDI – official 58.9mpg: True MPG 47.6mpg

We think the entry-level E220 CDI Cabriolet makes the most sense. We still recommend SE trim to get the most comfortable ride, and the seven-speed automatic gearbox to get the smoothest gearshifts. In this combination, it’s a classy, commendable cruiser that also manages to return 47.6mpg.

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

For a mid-size convertible, the Cascada has a particularly roomy interior with genuine space for four adults. It’s also a refined car on the road, with little flex through the body and the standard suspension does a good job of filtering out pockmarked roads. The heavy body does make it feel inert at times and compared to rivals it is expensive.

5. Audi A3 Cabriolet 2.0 TDI – official 67.3mpg: True MPG 46.3mpg

The best four-seat diesel convertible you can buy. The Audi A3 Cabriolet is refined, comfortable and returns decent fuel economy even if its True MPG figure is more than 20MPG off the official figure.

6. Citroen DS3 Cabriolet 1.6 VTi – official 49.6mpg: True MPG 45.2mpg

Small convertibles don’t come much more stylish than the DS3 Cabriolet, although the retractable fabric roof is more of a big sunroof than a full drop-top. Still, it can be put back in place at up to 74mph. The DS3 is good to drive, with this 1.6 VTi engine being the best match for leisurely motoring.

7. Volkswagen Beetle Cabriolet 1.2 TSI – official 47.9mpg: True MPG 35.8mpg

The Volkswagen Beetle Cabriolet is not the most entertaining car to drive, but its styling will more than justify any handling niggles for most owners. Otherwise, it’s a comfortable, refined place to be. Don’t expect to use it as a full-time four-seater, though, because the rear seats are cramped.

8. Porsche Boxster 2.7 – official 34.4mpg: True MPG 34.9mpg

The Porsche Boxster is an utterly sensational sports car. It's beautiful to look at, suitably epic to drive, and makes a good ownership proposition, especially considering our True MPG team was able to beat the official fuel figure.

9. BMW Z4 Roadster sDrive28i – official 41.5mpg: True MPG 32.7mpg

The BMW Z4 looks and drives like a proper sports car, and it makes you feel special every time you get in. It's also the third BMW in this list, returning 32.7mpg in real-world testing from its petrol engine.

10. Audi TT Roadster 2.0 TFSI 230 quattro – official 42.2mpg: True MPG 32.4mpg

The Audi TT Roadster is brilliant to drive and easy to live with. This is nowhere near the most economical model in the TT Roadster range thanks to the four-wheel drive system, however it still manages to return more than 32mpg.

We add new models 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.


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