A man loads gear into his rooftop cargo carrier on a car that is parked by a glass building.

Everything you need to know about cargo boxes

In this guide you’ll learn about the different types of cargo boxes, cargo box sizes, and which is the best cargo box for you.

Thule has a wide range of cargo boxes, for both the roof and trunk of your car. For vehicles that can handle weight on the roof, our roof boxes are roomy and easy to install. For cars that have a towbar or hitch, it might be a rear cargo carrier you are looking for.


Scroll down to learn more about:

A close-up of a person loading their skis into a Thule ski box.

Cargo box fit guide: Find the best rooftop cargo carrier


Find the best rooftop cargo carrier for your vehicle and lifestyle with this Thule cargo box fit guide!


Cargo boxes are a great way to increase the packing capacity of your car. Whether you’re hitting the slopes, going on a family vacation, or just need more space, a cargo box is a super versatile solution.


But with all the different types of cargo boxes and cargo box sizes, how do you know it will fit your car? And how can you make sure it will fit all the things you want to pack?


This Thule cargo box fit guide aims to clear some of this up. We’ll show you how to make sure the cargo box fits your car and how much you can pack inside the different cargo box sizes.


In this article we’ll go through:

Find the best rooftop cargo carrier for your lifestyle

A close-up of a woman grabbing her skis from an open roof box with Thule duffels inside.

Finding the best rooftop cargo carrier is all about first deciding what you want to do with it. Maybe you only need to pack your skis, or camping gear, or a little bit of both?

Here are some of our picks for the best roof cargo boxes according to the adventure you’re planning:


The best ski cargo boxes and snowboard boxes:

Almost all Thule roof boxes double up as ski boxes or snowboard boxes. The roof boxes that are size L and larger can fit from 3 to 7 skis and from 3 to 5 snowboards.

Thule ski boxes in Alpine size are low-profile boxes that are specifically designed for skis. They sit lower on the car for a sleek style and better aerodynamics. These boxes function best as ski boxes and not bulky cargo.

Some recommended ski cargo boxes:

Cargo boxes for travel:

If you plan on using your roof box for long road trips across state lines or national boarders, the roof box you choose should be higher to hold bulky gear.

For sporty types who want to bring a bike or a kayak along on their trip, opt for a narrow “sport” sized roof box. These will leave more space on your roof rack for a bike or kayak rack.

Some recommended roof boxes:

Cargo boxes for extra space:

It’s a popular option for city-dwellers with small cars to add a roof box to maximize their packing space. If you’re using a roof box for everyday chores like packing your kid’s stroller, groceries, or a suitcase to the airport, a smaller size roof box will do.

Some recommended roof boxes:


Cargo Box Sizes

So, you know you want a cargo box, you’re just not sure how to choose the right size? Cargo box sizes range from S to XXL. But what size is best all depends on what you’re packing.

This cargo box fit guide helps you choose the right cargo box for everything you’re packing. At Thule, sizes include S, M, L, XL and XXL. Packing these boxes can look something like this:


Cargo box S (8 cu ft / 300L):

Fits roughly: 3 people (2-3 60L bags)

Perfect for: A trip with your partner, family or friends for a weekend getaway.


Cargo box M (11-14 cu ft / 360-400L):

Fits roughly: 4 people (3-5 pairs of skis, or 3-4 60L bags)

Perfect for: A camping trip or outdoor adventure with your family or friends


Cargo box L (13-16 cu ft / 380-450L):

Fits roughly: 4 people (5-7 pairs of skis up to 180cm, or 3-4 skis + 4 60L bags)

Perfect for: A family ski trip or outdoor camping trip

(see image below)
A flatlay of the Thule Vector L roof box featuring all the ski gear you can fit inside.
Cargo box XL (18 cu ft / 500L):

Fits roughly: 5 people (5-7 pairs of skis up to 200cm, or 3-4 skis + 5 60L bags)

Perfect for: A family ski trip or outdoor camping trip (that needs even more packing space)

(see image below)
A flatlay of the Thule Motion XT XL roof-box-featuring all the ski gear you can fit inside.
Cargo box XXL (22 cu ft / 610L)

Fits roughly: about 6 people (5-7 pairs of skis up to 215cm, or 4-5 skis + 6 60L bags)

Perfect for: A ski trip or outdoor adventure with a large family or friend group

Also, always remember: You can’t pack more than the maximum weight capacity of your car roof or the load capacity of the roof box itself.


Comparing our boxes: Thule Force XT vs Thule Motion XT vs Thule Vector

Thule Force XT, Thule Motion XT and Thule Vector are three state-of-the-art roof boxes that are designed for increased aerodynamics and enhanced user-friendliness. So, what exactly are the differences?

What they all have in common:

  • All three boxes have dual-side opening meaning that you can easily open the box from either side of the car.
  • They are designed to be as aerodynamic as possible.
  • They’re all constructed with hardy ABS plastic which is impact resistant.
  • They also use PowerClick mounting hardware, so that you always know you’ve mounted the box to your roof racks correctly.
A car drives in a snowy forest with a Thule Motion XT rooftop cargo carrier.

Thule Vector

These cargo boxes are the most premium of the lot. They have all the features of the Thule Motion, plus more for even smoother usability.

The felt lined interior gives your gear extra protection, and the white lid and LED light helps you see your packing in the dark.

The reinforced lid on the Thule Vector is the strongest and gives the box extra protection from impact (although all Thule cargo boxes are built to withstand lots of force).

A car with a Thule Vector rooftop cargo carrier is parked in a snowy forest.

Thule Motion XT

These boxes can go up to XXL sizes, the largest Thule cargo box size. It has a handlebar which makes the box easier to open.

It also has the SlideLock system, a super handy feature which makes closing your box super simple. It means that the box automatically shuts when closed, so that you can close it with just one hand. The lock indicates when the box has been shut correctly with a red indication button.

A car drives in a snowy forest with a Thule Motion XT rooftop cargo carrier.

Thule Force XT

Thule Force XT is a versatile cargo box you can rely on to carry all kinds of cargo.

It’s easy to mount on your roof racks and clicks when it’s properly mounted so that you know you’ve secured it correctly.

It can also be opened on either side (which you’ll be thankful for when you park on different sides of the street).

Large versus small cargo box:

Large cargo boxes are of course great because they can fit tons of gear. But keep in mind that they affect the fuel economy more than smaller boxes.

That said, Thule roof boxes are designed to be some of the most aerodynamic boxes on the market, especially the more low-profile Alpine sizes. So even with a large roof box your ride will be a smooth one.


How to make sure the cargo box fits your car or SUV

When choosing a cargo box, double check that it will fit your vehicle. Here are some things to pay attention to:


Hatch Clearance:

A close-up of a car with a hatch that is open even with a Thule rooftop cargo carrier on the roof.

Hatch clearance means that your trunk can be opened completely without interfering with the roof box. Thule roof boxes are designed specifically so that you can open your hatch without a problem.

Unsure if you’ll be able to open your car’s rear door with your new box?

This is how you can calculate the hatch clearance:

An illustration that shows what parts of the car roof to measure to determine hatch clearance.

1. Hatch Clearance:

  • Open your trunk door completely.
  • Measure from the center of your vehicle's front roof rack to the point where the roof meets the hatch.
  • Compare this number to the "Front Clearance" dimensions that are specified in the roof box’s user manual. If your vehicle measures greater than the number listed, that cargo box will fit your vehicle without contacting your hatch.

2. Bar spread:

  • Also, have a look at the maximum bar spread. This is the distance between your roof racks. If your bar spread is the right size according to the roof box’s user manual, then you’ll have full access to the trunk.

Some roof racks can be moved further forward on your vehicle. If possible, this might also help allow for hatch clearance.

Remember the roof racks!

Thule roof boxes are mounted on the roof racks of your car. If you have roof racks already, make sure they’re compatible. If you don’t have roof racks yet, we have some great options!

How much can you pack in your roof box?

That depends on the maximum roof load of your car or your roof box.

Thule roof boxes have a load capacity of about 75kg/165lbs and most vehicles have the same maximum capacity. Double check with your car manufacturer to see if that’s the case for your car.

In general, when packing your roof box, try to pack lighter, bulkier items like tents, clothes or sleeping bags.



Packing your roof box

For the smoothest possible ride, try to pack your cargo box with the proper weight distribution.

Half of your gear should go in the space between the roof racks. The second half should be organized at either end of the roof box.

An illustration showing how you can pack your Thule rooftop cargo carrier.

Cargo box for an SUV:

Cargo boxes can fit a wide range of vehicles, not just sedans and hatchbacks. Cargo boxes for SUVs are the same as cargo boxes for any other vehicle. If your SUV has the right hatch clearance and bar spread, the cargo box will fit your SUV.

Cargo boxes are also perfect for vans and trucks. They fit securely on Thule truck and van roof racks with the help of an adapter.



Can I use a rooftop cargo carrier with my electric car?


This depends entirely on the electric car itself. Some electric and hybrid cars don’t allow anything to be loaded on the roof. But that doesn’t mean you have to spend your days box-less!

Rear cargo carriers are a great solution for electric or hybrid vehicles that can’t handle anything on the roof. These are cargo carriers that fit on the back of your vehicle either on the towbar or hitch receiver. These can also be packed full of gear for a camping vacation or road trip.

If you have a high car and want a storage solution that is lower down to the ground, rear cargo carriers might also be a good option for you.


A car has a Thule Arcos towbar cargo carrier and a man gets out of the car and a family walks towards him.

Rear-of-car solutions

Rear-of-car cargo solutions are great for those who don’t want anything on the roof of their car. With a rear cargo box you can optimize the range of your vehicle and turn your compact city car into an adventure car!

You don’t have to buy a big vehicle to transport your family and gear. Our rear cargo boxes turn your compact car into the perfect family car where you can store the gear you need for everyday errands, a day at the golf course, or a trip to your summer house.

The advantages of a rear-of-car solution

The rear of a car with Thule Arcos towbar cargo box, where it is completely integrated.
Bring all your gear without compromising on the range of your electric or fuel-driven car
A vehicle drives down the road with a towbar cargo carrier mounted to the back.
Works for vehicles and EVs that don’t let you load anything on the roof
A vehicle is parked in a field with a towbar cargo box and a rooftop tent.
A versatile solution that turns a small car into an adventure car
A white SUV drived with a bike and kayak on the roof, a towbar cargo box on the trunk.
Easy to pack and saves space on the roof for more gear

Optimizes the range of your vehicle

Rear-of-car solutions take you and your gear farther...

Rear cargo boxes have no impact on your battery or fuel consumption*. Thanks to the rear cargo box’s location at the back of the car, it’s a spot that naturally causes very little wind drag. With a rear cargo carrier, you can pack your vehicle full of gear without majorly impacting the range of your electric vehicle or fuel-driven car. This will help you save on fuel or electricity costs.

A sketch of the Thule Onto rear cargo carrier and the aerodynamic design.

For electric vehicles that can’t handle a heavy roof load

Certain electric vehicles have restrictions on roof load capacity. With a rear-of-car cargo carrier solution, you don’t have to worry about this. Simply attach your bike rack or cargo carrier to your towbar and get ready for the adventure.
A vehicle is parked next to a dirt road with a towbar cargo box mounted on the back.

Bring more, go farther

When we say that rear-of-car solutions take you farther, we really mean farther. Both internal testing at the Thule Test Center and testing by external sources have shown that a towbar box leads to less fuel or electricity consumption than having nothing on the car at all.
A woman loads items into the trunk of a car while her children help load items into the rear towbar box.

Get better range with a rear-of-car cargo box

We know from data models and wind tunnel tests at the Thule Test Center that a rear-of-car cargo solution makes for better aerodynamics than having nothing on your vehicle at all.

It may seem strange at first – how can you possibly lower the air resistance by adding a large cargo box to the back of the car? But the results speak for themselves.

We drove a total of 5400 km in varying weather conditions with a fleet of Volkswagen ID4 – one of the most popular electric vehicles on the market. The results were interesting, to say the least.

The average consumption (kWh/100km) of a vehicle with the Thule Arcos towbar box was 95 %. This means that when we drove the Volkswagen ID4 with Thule Arcos mounted, the range improved by 5%* compared to the cars with nothing on them at all. So based on the battery of size of the ID4 and the consumption measured during the tests, we could travel roughly 17 km further*. This data is also backed up by computer simulations that showed a similar result.

We were able to drive farther – and at the same time, we could bring more gear.

A vehicle drives down the road with a towbar cargo carrier mounted to the back.

Tested in real life

This is supported by an external test by Vi Bilägare, Sweden's largest car magazine. It was founded in 1930 and features travel reports and test drives of cars and car accessories. They tested a roof box and our Thule Onto rear cargo box with both electric and fuel-driven cars.

Vi Bilägare found that the towbar cargo carrier created less wind drag than a roof box, and consumed less fuel and electricity than a car with nothing on it at all.

“One way to get more packing space without increasing energy consumption is the latest trend of mounting a cargo box on the car's towbar,” they explain in their article, “We found that both the petrol car and the electric car had slightly lower consumption with the box fitted than when the car was running completely empty on the test route”.

Read the article from Vi Bilägare (in Swedish).


A versatile solution

Rear cargo carriers are a versatile solution that gives you a range of creative ways to maximize the packing capacity of your vehicle.
A vehicle is parked in a field with a towbar cargo box and a rooftop tent.

Turn your compact city car into an adventure car

A rear cargo carrier lets you use your compact city car in a variety of ways. Load on your bikes and head out into the unknown one day, and pack your bags for a weekend trip the next. The choice is yours, we provide you with the solutions.

By the ocean, a white SUV drived has a bike and kayak on the roof, a towbar cargo box on the trunk.

Saves space on the roof

A rear-of-car solution saves space on the roof of your vehicle for other sports carriers. Why not put your luggage in the back, and your bikes or board on the roof?
A woman loads items into the trunk of a car while her children help load items into the rear towbar box.

Easy to pack your gear

Certain rear cargo carriers are tiltable, others sit very low down – but both kinds let you easily access the trunk of your car at any time. A rear cargo carrier is also easier to load or unload, since it’s closer to the ground.

Our rear-of-car solutions


Recommended rear cargo boxes

Thule Arcos is the most aerodynamic option and is perfect to use in the city with your compact electric vehicle. The hard-shell exterior makes it robust and stable, and the low-profile, curved design means you can access your trunk at any time. This sleek, modern rear cargo box is a natural extension of your car.

Thule Transporter Combi is a hard-shell cargo box with a tilt-down design for partial access to the trunk even with gear loaded. It's perfect for everyday errands or adventures off in the outdoors.

*Internal tests at Thule show that our rear cargo boxes have an improved effect on the range of your vehicle. However, many parameters can affect your vehicle’s fuel consumption or battery range. Therefore, you may see results that differ from ours.
*Internal tests at Thule show that our rear cargo boxes have an improved effect on the range of your vehicle. However, many parameters can affect your vehicle’s fuel consumption or battery range. Therefore, you may see results that differ from ours.

In the sunset, a family parked by the water with a car that has a Thule Arcos cargo box.

Pros and cons – why choose a towbar cargo carrier?

Why choose a towbar cargo carrier? Here are some towbar cargo carrier pros and cons so that you can choose the best cargo carrier solution for you.

Towbar cargo carriers are a great way to bring the gear you need for fun outdoor adventures, they’re also a smart way to add more storage space to a compact city car.

Towbar cargo carriers are a great way to bring all the gear you need for fun outdoor adventures, they’re also a smart way to add more storage space to a compact city car.

But what exactly is the difference between a roof box and a towbar cargo carrier, and which one will fit your lifestyle the best?

In this guide we’ll dig into the pros and cons of towbar cargo carriers, and compare them to traditional rooftop cargo carriers.


A world of possibilities at the back of your car

Rear-of-car solutions take you and your gear further...

A sketch of a vehicle with the Thule Onto towbar cargo carrier in the back of the car.
Towbar cargo boxes are the most aerodynamic solution thanks to their position at the back of the car.

...get more out of your vehicle...

...utilize your electric vehicle in ways you didn’t know were possible

A vehicle is parked next to a dirt road with a towbar cargo box mounted on the back.
Certain electric vehicles have restrictions on roof load capacity. With a rear-of-car cargo carrier solution, you don’t have to worry about this. Simply attach your bike rack or cargo carrier to your towbar or trunk, and get ready for the adventure.

Unsure whether to choose a rear cargo box or a roof box?

A vehicle is parked in the snow next to a snowy forest with a Thule Vector roof box.
Roof boxes are designed to be as streamlined as possible to decrease wind resistance. Thule designs some of the most streamlined boxes on the market. Rooftop cargo carriers are also the best option to transport your skis or snowboards. Keep reading below to see more differences!

Towbar cargo carrier pros and cons

A couple look out at a car is parked in the grass in the mist with a Thule Arcos towbar cargo box.

Pros of a towbar cargo carrier:

  • Super aerodynamic. Thanks to the towbar cargo box’s location at the back of the car, it’s naturally an aerodynamic spot that causes no impact on your fuel consumption or the range of your electric vehicle*

  • Less wind drag means you use less fuel and electricity while driving with your gear packed

  • The boxes’ aerodynamic nature also makes them super quiet when you’re driving

  • They give you the option to store gear even if your vehicle – like certain e-vehicles – doesn’t let you put anything on the roof

  • Great if you want to leave space on the roof racks for other sports carriers

  • The towbar cargo carrier is closer to the ground which makes it easy to pack heavy items. If you’re a parent in a rush, for example, you’ll appreciate being able to throw your stroller in the rear cargo box without having to do any high lifting

  • Certain towbar cargo carriers can be combined with a bike rack

Cons of a towbar cargo carrier:

  • You take up more space at the rear compared to a roof box, which might make it harder to parallel park

  • Since towbar cargo carriers can’t carry skis – a roof box or a ski rack is a better option for a ski holiday

Towbar mounted cargo carrier vs roof box

Aerodynamics

A black vehicle is parked on the street with a black Thule Vector roof box.

Roof boxes are designed to be as streamlined as possible and Thule designs some of the most aerodynamic boxes on the market. They are a great option for vehicles that can carry something on the roof.

A vehicle with the Thule Arcos hitch caro carrier is parked in the woods by a lake.

Towbar cargo carriers, on the other hand, have the advantage of being at the back of the car in a place that barely affects wind resistance at all.

Towbar trailer cargo carriers like the Thule Arcos generate little to no wind drag. This means that, with a Thule Arcos towbar cargo carrier, you’ll be using the same amount of gas or electricity as a vehicle without anything on it.

They’re a great option for those who do not want to carry anything on their roof.

Position on the vehicle

Towbar cargo carriers are installed at the back of your vehicle. This makes them ideal for e-vehicles or other cars that cannot handle a heavy load on the roof.

Roof boxes, on the other hand, are positioned on the roof (pretty obvious considering their name!) and this can be handy, too. All roof boxes let you use the trunk as normal, and Thule roof boxes are specifically designed to not interfere with the trunk door.

If you want access to the trunk with a towbar cargo carrier you have to specifically choose a box that swings away, tilts down, or sits low enough so that you still have access to the trunk. Thule Arcos has a curved design and sits low down so that you can access the trunk whenever you need to.

An advantage with the positioning of the rear cargo carrier is that it’s lower down to the ground. This makes it really easy to pack all your stuff, since you don’t have to strain or stretch to reach your box.


When carrying bikes or skis

Carry bikes at the back of your vehicle

If you want to carry bikes at the back of your vehicle, towbar bike racks let you do just that.

Some towbar bike cracks even double up as a rear cargo box! Thule VeloSpace is a towbar bike rack that can be fitted with the Thule BackSpace XT and used as a cargo carrier instead. This means you can pack groceries or camping gear one day, and go for a bike trip the next.

Carry skis on the roof of your car

Roof boxes are a great option for transporting your skis. Especially the alpine-sized Thule roof cargo boxes, which are specifically designed for long skis up to 200cm. The largest Thule roof boxes fit skis up to 215cm. To find the right size for your skis, check out our guide on roof box sizes.

Remember the roof racks!

Thule roof boxes are mounted on the roof racks of your car. If you have roof racks already, make sure they’re compatible. If you don’t have roof racks yet, we have some great options!


Related products