BMW 4 Series Convertible (2021-present): dimensions and boot space

Here are all the key measurements for the BMW 4 Series Convertible, including length, height, width and boot size

Matt Rigby
May 24, 2022

Many convertible models are two-seaters only, but if you need to accommodate rear-seat passengers occasionally, yet still want the enjoyment of open-air motoring, then the BMW 4 Series Convertible could well be for you.

This version, introduced in 2021, drops the previous model’s folding hard-top for a simpler, lighter fabric roof - meaning more luggage space and rear-seat room, as there’s a less bulkily shaped roof to stow away.

The overly large ‘flared nostril’ grille arrangement on the front of the car might put some potential buyers off, but overall the styling is sleek and sporty, just like the 4 Series Coupe upon which the car is based.

Engine options include a variety of petrol and diesel models, ranging from the 190hp 420d diesel and 184hp 420i petrol to the high-performance 340hp M440d xDrive diesel and the 374hp M440i xDrive petrol, with every version being fitted with a slick eight-speed automatic gearbox.

As you might expect, given BMW’s reputation, all versions are fun to drive - especially the faster models - and, like the coupe version, the convertible 4 Series is lower and wider than the 3 Series Saloon and Touring models that it’s otherwise closely related to, making it look and feel more sporty.

The interior is all but identical to the 3 Series up front, which means that the dashboard, with its clear touchscreen media system and configurable digital driver’s display, is well laid out and feels very well made.

The 'iDrive' media system's rotary controller is a bonus, too, as it means you can make tweaks to the sat-nav or radio settings while on the move and without having to take your eyes from the road more than necessary. There’s plenty of standard equipment, too, including heated leather seats, three-zone climate control and cruise control.

The rear seats are, naturally, a little less comfortable and spacious than in the fixed-roof coupe, as the need to stow the hood robs rear-seat passengers of a little room. Headroom is also a little tight in the back with the roof up. That said, it’s as good as any of its rivals, and fine for a pair of six-footers, as long as you’re not going on too long a journey.


BMW 4 Series Convertible dimensions

The main dimensions of the 4 Series Convertible are actually the same as the regular 4 Series Coupe’s. That makes it 4,768mm long, 1,852mm wide (rising to a little over 2m if you count the car’s door mirrors) and 1,383mm tall. This means that the Convertible is lower and wider than the 3 Series Saloon, which helps make it look more purposeful and sporty.

The Audi A5 Cabriolet and Mercedes C-Class Cabriolet are almost identical in their dimensions, so there’s not much to differentiate them, aside from the fact that the Mercedes is a little taller at 1,409mm.

All three cars are therefore quite large but still relatively low, but the fabric hood in the BMW makes over-the-shoulder visibility a little limited when the roof is up. That’s solved by the standard-fit parking sensors when pulling into a space, though it doesn't help when changing lane on the move.

BMW 4 Series Convertible4,768mm1,852mm1,384mm
BMW M440i/M440d xDrive4,770mm1,852mm1,394mm
BMW M4 Competition Convertible4,794mm1,887mm1,395mm

BMW 4 Series Convertible boot space

BMW 4 Series Convertible boot view

Although the 4 Series Convertible has a smaller boot than the regular coupe - with its 385 litres of capacity being 55 litres short of what you’d get in the hard-top - it’s still reasonably spacious. That’s still more than you’d get in a Ford Focus or Volkswagen Golf, so it's pretty spacious, although the shape of the boot and the tailgate aren’t as useful as a hatchback’s. It's also worth remembering that the 4 Series is a much longer car than the Focus and Golf.

Another issue is that, when you put the roof down, you lose more space still. Although this is common for convertibles, it is a limitation in the practicality of the 4 Series, as boot space drops down to 300 litres.

Overall, though, the 4 Series Convertible still offers a little more boot space than the Mercedes C-Class Cabriolet, although the Audi A5 Cabriolet provides a slightly bigger boot, so it's worth considering if you want a four-seater convertible with the most practical boot possible.

Boot spaceBoot space
BMW 4 Series Convertible385 litres


BMW 4 Series Convertible towing capacity

A sleek two-door convertible might not be the natural choice for a tow car, but the sturdy 4 Series is no lightweight, making it a relatively stable platform from which to pull a trailer. The range of powerful engines makes hauling a horsebox or caravan along a pretty effortless affair, too.

In terms of specific numbers, the 4 Series Convertible is rated as being able to pull up to 1,800kg, but that’s only for the more powerful models. The 420d and 420i, for example, are rated at a slightly less impressive 1,600 kg.

The four-wheel-drive 'xDrive' models are useful, too, in that they provide extra traction that could be very useful in getting out of a muddy field with a horsebox or other trailer attached.

BMW 4 Series Convertible weight

BMW 4 Series Convertible rear view

The kerb weight is the best way to assess how heavy a car is, because it includes the fluids for the engine, a tank of fuel and 75kg to account for the weight of a driver.

In the case of the 4 Series Convertible, the car weighs between 1,690kg (for a two-wheel-drive 420i M Sport) and 1,980kg (for a four-wheel-drive M440d xDrive). This is because diesel engines are heavier, and the four-wheel-drive system adds further weight.

The convertible is also around 150kg heavier than an equivalent 4 Series Coupe, owing to the extra chassis strengthening required for a soft-top design. The M4 Competition Convertible, meanwhile, is even heavier at 1,995kg.

BMW 4 Series Convertible1,690kg - 1,980kg
BMW M4 Competition Convertible1,995kg



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