Car roof storage buying guide

Car roof storage boxes, also known as cargo boxes, are storage spaces that are mounted to your car’s built-in or installed roof racks. The extra storage space can make it easy to transport bicycles, ski gear, fishing equipment and other large items. Use our guide to help you compare different sizes and features of car roof boxes so you can choose the right one to meet your travel needs.

Compare some of the best car roof boxes

Name	Avg. price (USD)	Type	Capacity	Dimensions	Purchase
Thule Sidekick Cargo Box	$299	Hard	75 lbs	54″ x 25″ x 15.5″	Buy now
Yakima Skybox Lo Carbonite Cargo Box	$599	Hard	15 cu. ft.	92″ x 36″ x 11.5″	Buy now
Seattle Sports Sherpak Go!15 Waterproof Cartop Storage Cargo Bag	$86	Soft	15 cu. ft.	15.5″ x 37″ x 45″	Buy now
Rhino-Rack MasterFit RMFT550	$588.93	Hard	14 cu. ft.		Buy now
RoofBag Waterproof Car Rooftop Storage Bag	$69	Soft	15 cu. ft.	48″ x 38″ x 18″	Buy now
J*EGS Performance Products 90098*	$179.99	Hard	18 cu. ft.	57″ x 39″ x 19″	Buy now
Thule Motion XT Rooftop Cargo Carrier XL	$749.95	Soft	18 cu. ft.	84.5″ x 36″ x 17″	Buy now

What size and shape do I need?

When choosing a roof storage box, the most important factor to consider is its size and shape. Roof boxes are usually rectangular, but their dimensions vary. It’s more helpful to compare the dimensions of the roof box, rather than its stated capacity. Check the dimensions of the roof box against the dimensions of your car — you’ll want to be able to open your car’s tailgate completely without the spoiler hitting your box.

Roof storage boxes come in half-, medium- and full-widths, in both long and short options. With a half-width box, you can carry additional gear on your roof, such as a bike or canoe. Medium-width boxes typically suit a family of four. A long, full-width roof box that covers your whole roof offers more storage space but requires two people to maneuver it. A long roof box would suit those carrying skis.

Standard roof box sizes

Height restrictions

When adding a roof box, check the increased height of your car and be aware of height restrictions for tunnels, parking lots and other height-restricted spaces. Height restrictions in the US depend on the location and the road.

Before buying a roof box, check the following heights:

• Car
• Roof box
• Roof rack

Add the three heights together to get the total height of your vehicle with the roof box, then add an extra margin of at least a few centimeters just to be safe. To find out the height of your car, check your car manual. If you’re storing anything additional on your car, such as an upright bicycle, measure from the highest point.

Once you’re on the road, keep an eye out for low-clearance roads, tunnels, underpasses and parking lot entrances.

How to compare car roof boxes

A car roof box can cost you from around $499 up to $2,000, depending on the size of the box, the material used and the brand. To work out which roof box is right for you, consider these features:

Durability

Does your roof storage box need to withstand extreme changes in temperature, wet conditions or high impact? If so, consider a higher-end material. Cheaper boxes are generally made of a thinner plastic that could become weak with prolonged use and crack in cold temperatures. Opt for UV-protected ABS plastic or fiberglass reinforced plastic that will better withstand wear and tear, as well as rain, extreme temperatures and high impact.

Waterproofing

If you want your box to be fully waterproof, look for a flush-fitting lid and base design.

Locking system security

Do you want a secure locking system or are you happy with a simple, single-lock design? Higher-end options generally offer better security. A single lock in the middle may be easier to pry open from the sides and allow easy access to your items. A box with multiple locks or a central locking system is ideal for safety. However, boxes with a central locking system can be difficult to close.

Dual side openings

Roof boxes that can open from both the left and right sides tend to be more practical. Rear-opening boxes provide access from three sides at once.

Accessories

There are various roof box accessories you might want to consider:

• Cover. Purchasing a roof box lid cover is not essential, but good if you want to protect your box from scratches and dirt while it’s stored.
• Light. This will be helpful when you’re trying to unload your box in low light conditions or at night.
• Ski carrier. Some boxes offer specific ski carriers to hold your skis securely inside the box. Other boxes feature a “safety nose” — an extra internal energy-absorbing barrier to prevent skis from breaking through the front of the box during a collision.
• Wall holder. You might want to use a wall holder in your garage to store your roof box when it is not in use to prevent damage from scratches.

Alternate storage options

If you don’t want to shell out the money for a roof storage box, soft-sided roof bags or roof baskets can give you additional storage for a lower cost. If you only want to transport your bicycles, you could also opt to get a tow bar or trunk-mounted bike rack instead of investing in a roof box.

Bottom line

Adding a storage box to your vehicle’s roof can be an easy way to make sure nothing gets left behind on your trip. These products range in price and quality, so compare a few models before settling on the best fit for your on-the-go storage needs.

Frequently asked questions

Do I need a roof rack to use a roof storage box?

Yes. If you want to attach a roof box to your car, you’ll need a roof rack. Though your roof box doesn’t have to be a particular shape for your car, your roof bars do. Check what roof racks fit your car by finding out your vehicle’s roof type.

How should I store my roof storage box?

If you’re planning on using your roof box only occasionally, we recommended that you store it horizontally instead of upright, which can cause damage to the end or side of the box. If space is an issue, you can purchase a hoist system so that your box can be suspended from your garage roof, or use a wall holder to keep it securely mounted against the wall. Roof boxes should be stored in a cool, dry place out of direct sunlight to avoid damage from extreme temperatures and UV rays.

What are the best brands of roof cargo boxes?

Just some of the leading brands in this space are Thule, Yakima and SportRack.