Towing capacity: how to work it out

The rules on what you can tow with your driving licence are different depending on when you passed your test. And the penalties for exceeding the weight limit of your vehicle and/or driving licence can be significant.

In this driving advice guide, we look at what towing capacity is, how to work it out and the rules you need to abide by when looking to legally tow using your vehicle. 

The towing capacity of your vehicle is the maximum weight it can legally tow. The maximum towing capacity may be listed on the V5C logbook or on a plate/sticker on the car itself (usually inside the driver's doorframe). However, it may not be safe or comfortable to do so, especially with a caravan or trailer that has a large box-like profile.

The towing capacity may be published within the handbook of the vehicle. It can also be calculated from the VIN plate, where line one is the maximum allowable mass and line two is the maximum trian mass. Simply deduct line one from line two and you have the vehicle towing limit.

For safe towing it is recommended by many towing experts that a novice should keep the fully laden weight of the caravan no heavier than 85% of the kerbweight of the tow car. This is known as the 85% rule. Bear in mind that it is a guide and not legally enforceable.  

To calculate this, you only need to know two key figures: the kerbweight of the car and the maximum mass of the caravan (called ‘maximum technically permissible laden mass’, or MTPLM).

If the mass of the caravan is 85% or less of the car’s kerbweight, the car will tow it with ease.

If it’s between 85% and 100%, be careful – only experienced caravanners should use that car to tow such a heavy weight.

But if the caravan is heavier than the car, then it is strongly recommended not to use it to tow that caravan. This calculation is known by experts as ‘outfit matching’.

You can find the kerbweight of your car in the owner’s manual, sometimes on a plate on the door sill or sometimes on the V5 registration document (look for the figure ‘G: Mass In Service’).

The weight of the caravan is usually listed on a plate near the door frame and in the owner’s handbook, but the manufacturer should also be able to tell you.

You also need to make sure that the maximum width of the trailer does not exceed 2.55 metres, and the maximum length of the trailer does not exceed 7 metres body length.

This length does not include the draw-bar or A-frame towing coupling at the front.

• A complete guide to towing a caravan
• Can electric cars tow?
• The complete caravan buyers’ guide

If you passed your car driving test before 1 January 1997, you are usually allowed to drive a vehicle and trailer combination up to 8,250kg maximum authorised mass (MAM), as long as it's within the weight limits of the vehicle.

If you passed your car driving test after 1 January 1997, you’re allowed to tow trailers up to 3,500kg MAM (again, as long as it's within the weight limits of the vehicle).

You should always check the weight limits of your driving licence before towing - the limits are shown on the back of the photocard.  

For further advice on towing, including useful tips on how to tow and trailer licences, read our complete guide to towing a caravan. 

Not every car is capable of towing a caravan, especially smaller cars - and you can forget about your hatchback being up to the challenge.

If you're still unsure about what car to use or you know your car is not suitable then it is well worth researching what cars can best tow a caravan.

If you need any accessories for your caravan, be sure to have a look at our range of caravan accessories over at the RAC Shop.