Numberwright Tow is a set of free towing weight checkers for caravans, campers and trailers in Australia, the USA & Canada and the UK. We don't store vehicle data and we don't give legal advice. It is part of Numberwright, a small family of practical calculators that show their work.
The tools run entirely in your browser — nothing you type is sent to a server.
Built and maintained by Numberwright. The checks follow the definitions published by motoring bodies, transport departments and vehicle makers listed under Sources. Found a mistake? Contact details coming soon.
Check your trailer or caravan against towing capacity, tow ball weight, GVM/GVWR, GCM/GCWR and axle limits at once. AU, US & UK. Free.
Check ATM, GTM, tow ball mass, GVM, GCM and towbar ratings for your caravan and tow vehicle in one go. Free Australian calculator.
See how much payload your trailer's tongue weight uses and check GVWR, GCWR, GAWR and hitch ratings. Free, for the US and Canada.
Check MTPLM, towing limit, nose weight, MAM, gross train weight and the 85% guideline for your car and caravan. Free UK calculator.