BMW 4 Series Convertible (2013-2020): dimensions and boot space

Every key dimension and measurement for the BMW 4 Series Convertible, including length, height, width and boot space

Matt Rigby
Jun 9, 2022

Thanks to its folding metal roof - when most of its rivals use a fabric hood system - the BMW 4 Series Convertible is pretty unusual when it comes to four-seat convertibles.

There are clear advantages to this type of folding roof, including improved security and greater refinement when you’re on the move, but the metal roof weighs a lot more than the fabric equivalent and it is less easy to fold away into a small space.

As a result, the 4 Series Convertible has less boot space than its direct competitors - when the roof is down - as well as less room for rear-seat passengers.

Nevertheless, it’s still a fun car to drive - more so than both the Mercedes C-Class Cabriolet and the Audi A5 Cabriolet, which are its closest rivals.

Engines are a variety of turbocharged petrol and diesel powerplants, ranging from the 190hp 2.0-litre 420d diesel and 184hp 2.0-litre 420i petrol model all the way up to the muscular 326hp six-cylinder 440i and 313hp 435d. At the very top of the range is the high-performance 450hp M4 Convertible, which is quite the rocketship.

Inside, you’ll be very familiar with the layout if you are acquainted with the BMW 3 Series saloon - upon which the 4 Series is based. But that’s really not a bad thing, because the way the dashboard and major controls are laid out is attractive and intuitive. It’s also well built.

You get plenty of standard equipment in every model, too. There’s leather upholstery, heated seats, climate control, and parking sensors as well as built-in sat-nav with every car, while models from 2016 onwards get the option of Android Auto and Apple CarPlay, too.


BMW 4 Series Convertible dimensions

At 4,638mm long, 1,825mm wide (more than 2 metres wide when you take into account the door mirrors) and 1,384mm tall, the BMW 4 Series Convertible isn’t exactly a compact sports car. In fact, it’s broadly similar in its dimensions to the 3 Series saloon, but is wider and lower, which gives it a sleeker, more sporty look in comparison to the 3 Series.

It’s around the same size as the Mercedes C-Class Cabriolet and the Audi A5 Cabriolet, though the Mercedes and Audi get more generous rear headroom and legroom. That's more down to the bulkier metal roof of the BMW, though, which has to fit somewhere when folded down.

The 4 Series Convertible is significantly larger than two-seat roadsters like the Porsche Boxster and BMW Z4, but is almost 10cm narrower and 15cm shorter than the four-seater convertible Ford Mustang, which is another alternative.

BMW 4 Series Convertible4,638mm1,825mm1,384mm

BMW 4 Series Convertible boot space

BMW 4 Series Convertible rear seat view

With 370 litres of available boot space, the BMW delivers a reasonable amount of boot space. However, when you want to fold the roof down, that luggage capacity is cut to just 225 litres. That’s quite a small space, and means you have to make a bigger sacrifice for roof storage than you would in any of the car’s main rivals.

This is because of the BMW’s metal folding roof, which can’t be packed away as neatly as the fabric hoods of its rivals, so takes up space that would otherwise be available for the boot.

In the Mercedes C-Class Cabriolet, for example, you’ll find that there is 360 litres of boot space with the hood up, which is not as substantial as the BMW’s hood-up boot, but this falls to 285 litres with the roof down - much more than you get in the BMW.

The Audi is the most generous overall, however, with 380 litres of room when the roof’s up and 320 litres with it folded down.

Boot spaceRoof upRoof down
BMW 4 Series Convertible370 litres225 litres


BMW 4 Series Convertible towing capacity

You perhaps wouldn’t initially consider a sporty convertible to be an ideal tow car, but the 4 Series Convertible is rated to carry a braked trailer of between 1,400kg and 1,800kg, depending on the engine and specification of the car, which is a decent amount for a medium car.

In fact, the 4 Series Convertible should make a reasonable vehicle for towing, because it’s relatively heavy (which helps with trailer stability), and the low-down power delivery of the diesel versions is helpful for getting moving easily when towing, too.

For more regular towing, however, a larger, heavier SUV such as the BMW X5 might be ultimately more appropriate - especially if you want to tow seriously heavy loads.

ModelTowing capacity
BMW 4 Series Convertible1,400kg - 1,800kg

BMW 4 Series Convertible weight

BMW 4 Series Convertible rear view

The most realistic measure of how heavy a car is is its kerb weight, which takes into account engine lubricants and fluids, a tank of fuel and an extra 75kg - to represent the approximate weight of a driver.

With the 4 Series Convertible, the weight is dependent on the car's spec, whether it’s got four-wheel-drive (which is heavier than the standard two-wheel-drive setup) and whether it has a manual or an automatic gearbox. Owing to the changes made to create the folding metal roof, the 4 Series Convertible is also noticeably heavier than the coupe version of the 4 Series by around 200kg.

The lightest model is the 420i SE with a manual gearbox, at 1,650kg, while the heaviest is the 435d xDrive automatic, with a big diesel engine, an automatic gearbox and four-wheel-drive. This tips the scales at 1,905kg.

BMW 4 Series Convertible1,650kg - 1,905kg



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