Where in the instruction manual can I find the maximum roof load?
11 September 2026
You can find your car's maximum roof load in the instruction manual, also known as the owner's handbook or owner's manual. Look in the table of contents for terms such as “daklast”, “dakbelasting”, or “roofload”. The value is almost always found in the chapter on technical specifications or loading, and is expressed in kilograms.
This information is crucial before you buy or install a roof box. The maximum roof load varies by car model and sometimes even by version of the same model. In the rest of this article, we answer the most frequently asked follow-up questions regarding roof load, weight, and safety.
Where in the instruction manual is the roof load stated?
The maximum roof load is stated in the instruction manual under the chapter “Technical data” or “Loading and transport”. Search using keywords such as “daklast”, “dakbelasting”, or the English “roof load”. The value is displayed in kilograms and applies as an absolute upper limit for everything you place on the roof, including roof racks and roof box combined.
Don't have the owner's manual at hand? Then there are two quick alternatives. Many car manufacturers publish the technical specifications of their models on their own websites. You can also consult the RDW license plate check via rdw.nl, where the permitted roof load is listed for most vehicles. Simply enter your license plate number and check the technical specifications.
Please note: some instruction manuals indicate the roof load as “0 kg” or do not mention a value. This usually means that the manufacturer has not approved roof racks for that model, not that you may carry unlimited weight. In that case, please contact the dealer or importer for an official answer.
What is the difference between roof load and payload?
The roof load is the maximum weight you are allowed to place on the roof of your car, including roof racks, roof box, and all contents. The payload is the total weight of passengers and luggage that the car is allowed to carry in its entirety. These are two completely different limits that both apply and neither must be exceeded.
A practical example clarifies this. Suppose your car has a maximum roof load of 75 kg and a payload of 450 kg. Your roof racks weigh 8 kg and you Hapro roof box weighs 15 kg. Then you have 52 kg left for the contents of the trunk. At the same time, the total weight of everything on the roof, together with the passengers and luggage in the car, counts towards the payload.
In practice, roof load is the limiting factor for people going on vacation with a fully loaded family car. Especially if you are traveling with four people and the trunk is also full, it is wise to calculate the total load capacity before you leave.
How do I calculate the maximum weight my roof box can weigh?
Subtract the weight of your roof racks from your car's maximum roof load. What remains is the maximum weight for your roof box, including all contents. Weigh your roof racks or look up the weight in the product specifications. The weight of the empty roof box itself also counts and is listed in the product information.
A step-by-step calculation looks like this:
- Look up the maximum roof load in your owner's manual (for example, 75 kg).
- Note the weight of your roof racks (for example, 6 kg).
- Note the weight of the empty roof box (for example, 14 kg).
- Subtract both: 75 – 6 – 14 = 55 kg available for volume.
Also allow for a safety margin. Weight shifts while driving, and on a bumpy road or during an emergency stop, the load exerts more force than the static weight suggests. A margin of 5 to 10 percent below the maximum roof load is a sensible rule of thumb.
Bee VDL Hapro We clearly state the weight of each roof box in the product specifications, so that you can make this calculation quickly and accurately.
What if the roof load of my car is unknown?
If your car's roof load is not listed in the owner's manual or if you do not have the manual, consult the manufacturer's website, the RDW license plate check, or contact the dealer. Never rely solely on an estimate or a value based on a comparable model, as the roof load can vary significantly depending on the version.
For older cars or import vehicles for which less information is available, there are still a few options. Body shops and specialized garages can sometimes assess the roof construction. Some roof rack manufacturers also offer online vehicle checkers where you enter your license plate or vehicle details, and the maximum load is automatically calculated based on the vehicle specifications.
What you definitely should not do is ignore the roof load or make a “reasonable estimate” yourself. An overloaded roof is not only dangerous for the stability of the car, but it can also lead to damage to the bodywork and has legal consequences in the event of an accident.
What happens if you exceed the maximum roof load?
If you exceed the maximum roof load, you significantly increase the risk of accidents. An overloaded roof raises the car's center of gravity, making the car less stable in corners and during evasive maneuvers. Furthermore, overloading can cause damage to the roof, the roof racks, and the car's mounting points.
The consequences are not only technical, but also legal and financial. In an accident where the overloading of the roof played a role, your insurer may refuse to pay the damage in whole or in part. You are then effectively driving an uninsured vehicle. Moreover, the police can impose a fine during a traffic stop if the vehicle is demonstrably overloaded.
In practical terms, overloading also affects driving behavior. The car steers more heavily, braking distances increase, and fuel consumption rises noticeably. At higher speeds on the highway, an overloaded roof box can also produce noise and cause vibrations that significantly reduce driving comfort.
Are you unsure if your load fits within your car's limits? Then feel free to contact us. contact us. We are happy to help you make the right choice, so that you can hit the road safely and worry-free.
Frequently Asked Questions
Am I allowed to mount a roof box if my car does not have roof rails?
Yes, that is possible in many cases. There are roof racks specifically designed for cars without roof rails, which are attached via the door trims or specific clamps on the roof channel. However, always check whether the roof rack manufacturer supports your specific car model, and keep in mind that the maximum roof load still applies regardless of the mounting type.
Does the weight of the roof racks count towards the maximum roof load?
Yes, absolutely. The maximum roof load applies to everything you place on the roof, including the roof racks themselves, the roof box, and all its contents. Many people forget to include the roof racks in the calculation and therefore unintentionally exceed the limit. Look up the weight of your roof racks in the product specifications or weigh them yourself for an accurate calculation.
How do I best distribute the load in a roof box?
Distribute the weight as evenly as possible across the width and length of the roof box, and place heavier items as low as possible in the box. This keeps the car's center of gravity as low as possible, which improves driving stability. Also ensure that all items are securely fastened and cannot shift while driving, for example by using organizers or nets.
Does a roof box affect my fuel consumption, and if so, by how much?
Yes, a roof box increases your car's aerodynamic drag and therefore fuel consumption, even when the box is empty. On average, you can expect an increase of 10 to 25 percent, depending on driving speed, the roof box model, and your car's aerodynamics. The effect is greater on the highway than in the city. Therefore, remove the roof box when not in use to avoid unnecessary fuel consumption.
What are common mistakes when mounting a roof box?
The most common mistakes are: not securing the roof box firmly enough, causing it to shift or come loose; not periodically rechecking the mounting bolts after the first few kilometers; and positioning the box too far back or forward, resulting in uneven weight distribution. Always check that all fastenings are still securely tightened after the first 50 kilometers, and repeat this regularly during a long journey.
How do I know which roof box fits my car in terms of size?
The correct size depends on two factors: the available space on your car's roof and the amount of luggage you want to take with you. Measure the distance between your roof racks and compare this to the minimum mounting distance required by the roof box, as stated in the product specifications. Also take into account the height of the box in combination with the maximum height in parking garages, which in the Netherlands is typically 2.00 to 2.10 meters.
Can I also use my roof box in the winter, and are there any extra things to keep in mind?
Yes, most roof boxes are suitable for winter use, but there are a few extra points to keep in mind. Regularly check that the roof box lock is not frozen and, if necessary, use a silicone spray to prevent this. Also, bear in mind that snow and ice on the roof box add extra weight that counts towards the maximum roof load, so remove this before departure. Additionally, check the seal of the box periodically so that moisture cannot damage the contents.