Towing Capacity Calculator

The lower of the braked towing limit and what is left of the gross combined weight once the car is loaded. With four people and luggage aboard, the combined weight rating usually binds first — which is why the real figure is below the spec sheet.

The car. It presses down on the towball and is carried by the vehicle's payload, so a 100 kg nose weight is 100 kg of the car's carrying capacity gone before anyone gets in. This is the limit people breach without realising.

Five to seven percent of the loaded trailer weight, and within the towbar's own limit. Below about 5% is the classic cause of high-speed snaking; loading heavy items over the trailer axle rather than at the back is what keeps it in range.

The VIN plate, usually in the door shut or under the bonnet, and the handbook. They vary by engine, axle ratio and specification within the same model, so a figure from a forum for the same car may not be your figure.

It is an offence in most jurisdictions and it invalidates insurance. Braking distances and stability both degrade sharply, and the failure mode — a snaking trailer at motorway speed — is very difficult to recover.