The two most important weights you need to check are (for the car) Gross Vehicle Weight (GVW), and for the caravan, Maximum Technically Permissible Laden Mass (MTPLM). These are the maximum weights of the vehicles when loaded to their limits.
It is these two added together that must not exceed 3500kg’s.
Note: it doesn’t matter if they are actually loaded to these amounts, it’s the maximum allowed load that counts.
MTPLM is quoted regularly and is easy to find for caravans, so not too difficult.
For cars the Gross Vehicle Weight (GVW) is hardly ever quoted but is vital to know (see note below). Caravan websites and magazines only quote the kerbweight of tow cars as they are very keen on the Kerbweight and the 85% Rule.
If you already own the car you intend to tow with and aren’t going to change it, then you can find the GVW on the VIN plate, but if you are looking to buy a car with towing in mind, finding the GVW for your prospective car is tricky, but a great resource (for newer cars) is available here:
To use that website choose the car, including the specific model then click on “Technical Info” for details of Gross Vehicle Weight, Towing Capacity etc.
Make a note of the GVW as it will be vital for choosing a caravan.
Once you have your car’s GVW subtract that from 3500kg and that is the max. MTPLM of the caravan you can tow.
Please be aware the GVW will vary by different trim levels in your chosen range and by gearbox choice, an auto gearbox weighs more than a manual and so your GVW will be higher for an automatic, which in turn will reduce the size of caravan you can tow to keep within the 3500kg limit.
Practical Caravan is a great resource for Tow Car information, but they omit the GVW from every review and specification listing. For the life of me I can’t think why – apart from it’s run by people who passed their test before 1997!