Towing weights and capacities: how much can you tow?

Not all vehicles are suitable for towing, but those that are have a set weight limit that they can tow both legally and safely. It is crucial that you check these limits before hooking up a trailer in order to prevent potentially severe damage to the vehicle or even an accident out on the road.

Your car’s handbook should tell you if it is capable of towing and the maximum weight that it can safely handle. Alternatively, this information is sometimes located on the Vehicle Identification Number (VIN) plate. It should also be on the car’s V5C registration document. If this information cannot be found, it is highly likely that your car is not suitable for towing.

Two maximum towing weights may be shown, one for a braked trailer and the other for an unbraked trailer.

If your trailer weighs over 750kg as it stands or when loaded, it must be fitted with a braking system that is in good working order. While some smaller trailers under 750kg may also have brakes fitted, these are not a legal requirement.

If you need to manually calculate your car’s maximum towing capacity, your vehicle’s weight will be displayed on the VIN plate or in the owner’s manual. As with towing weights, more than one amount will probably be displayed. You can expect to see the vehicle’s Maximum Allowable Mass (MAM), also known as the gross train weight (GTW), is the most the car and trailer can weigh when combined including any luggage, and the maximum axle loads for the vehicle.

The simplest formula to follow when working out your car’s maximum towing capacity is to subtract the car's Gross Vehicle Weight (GVW) from the MAM (or GTW depending on how it’s described for your car. Your car’s towing capacity will be total remaining.

For example, if the MAM is 5,000kg and your car’s gross vehicle weight is 3,000kg, you can tow a trailer weighing up to 2,000kg.

• MAM 5,000kg - GVW 3,000kg = 2,000kg max towing capacity

It is important to include the weight of any extra payload that you will be placing inside the trailer - such as luggage in a caravan or a horse in a horsebox. If you need some help in working out your total figure, you could purchase a towing scale or use an online calculator to reach an accurate figure

Whatever you are towing, it must never exceed the trailer’s MAM or the car’s maximum towing capacity. These must be treated as absolute limits and the sensible option is to keep well below them to be safe.

The accepted safe limit for a trailer or caravan’s weight is 85 per cent of the vehicle towing it. If your tow car weighs 2,000kg, then the trailer you are pulling should weigh no more than 1,700kg - 85 per cent of 2,000kg.

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