How to calculate the towing capacity of your vehicle.

A common question I have been asked is:

What is the max weight I can tow without breaking the law?

The first step is to check the manufacturers plate attached to your vehicle.

The plate can normally be found on a door pillar or under the bonnet on the front panel or bulkhead. More recent vehicles have them displayed on the door pillar.

The plate resembles the image below which is taken from a Skoda Octavia and includes the approval, chassis or VIN number (Vehicle Identification Number) and weights in kg.

On the sample plate below, the design gross vehicle weight or maximum authorised mass is displayed as 1955 kg. This is the maximum weight the vehicle is allowed including the weight of the vehicle, passengers and any load.

The second weight shown is the design gross combined weight or train weight. 3355 kg. This is the maximum load of the vehicle and trailer combined with passengers and cargo in the vehicle and trailer.

The formula to calculate towing capacity under manufactures specifications is:

Subtract the gross vehicle weight from the design gross combined weight.

In this case, 3355 kg – 1955 kg = 1400 kg

Therefore, this vehicle can tow up to a maximum of 1400 kg which would include the weight of the trailer and load.

All light trailers sold after 29th October 2012, must legally be plated.

The image below shows a typical weight plate for a trailer.

In this case the trailer has one axle with a max gross weight of 1300 kg.

The plate also shows an unladen weight of 300 kg.

Therefore, the imposed load or load the trailer can carry is up to 1000 kg, giving a combined trailer and load weight of 1300 kg.

Taking the sample plate used above from the Skoda Octavia, it could tow this trailer when fully loaded.

If a trailer is towed by a vehicle where the max gross weight of the trailer is greater than the towing capacity of the vehicle, the trailer cannot be legally towed when fully loaded.

For example:

A trailer has an unladen weight of 500 kg and a max gross weight of 2000 kg, the towing vehicle has a towing capacity of 1400 kg (example above), therefore fully loaded the towing capacity is exceeded. In order to legally tow the trailer, the trailer load cannot weigh more then 900 kg, (unladen weight 500kg + load 900kg = 1400kg).

Licensing Requirements for towing

Category B Licence – Car, Van or 4X4

A category B licence holder can drive a car, van or 4X4 vehicle in which the manufacturers design gross weight does not exceed 3500kg and is constructed to carry no more then eight passengers in addition to the driver.

The holder of a Category B licence can tow a trailer in which the design gross trailer weight does not exceed 750kg. A trailer with a design gross weight above 750kg can be towed, but only when the combined design gross weight of both vehicle and trailer does not exceed 3500kg:

i.e. vehicle design gross weight is 1955kg and trailer design weight is 1300kg, combined = 3255kg, allowing a category B licence holder to tow legally.


Category BE Licence – Car, Van or 4X4

A holder of a BE licence can tow a trailer where the combined gross weight of the vehicle and trailer exceeds 3500kg.

However, the design gross trailer weight (ie: trailer weight and load), must not exceed manufacturers design towing capacity. The maximum trailer weight that can be towed by a BE licence holder is 3500kg.

Therefore, the maximum combined vehicle and trailer weight is:

towing vehicle 3500kg + trailer 3500kg = 7000kg.




For enquiries or more information contact Brian Connor,

T (+353) 083 417 8669


Brian is an SQI (Suitably Qualified Individual) under RSA regulations and requirements, an Independent Motor Engineer/Assessor @ ABC Motor Engineers and a member of the IAEA since 2011.

Posted in BLOG.