GVM, Payload & Towing Calculator
Add up your accessories, people, water, fuel and gear to see how much of your payload is left. Towing? Tick the box to check the trailer against your towing capacity, tow ball limit and GCM.
How the GVM and payload calculator works
- Payload = GVM − kerb weight.
- Vehicle weight = kerb weight + everything you carry + the tow ball weight of the trailer. Water counts as 1 kg a litre, diesel as 0.84 kg and petrol as 0.74 kg a litre.
- Combined weight = vehicle weight + trailer weight, with the tow ball weight counted once. It must stay under your GCM.
Where to find your figures
- GVM, GCM, towing capacity and tow ball limit: the compliance plate, the owner’s handbook or the maker’s specifications for your exact model and year. The tow bar has its own plate, and the lower limit applies.
- Kerb weight: the handbook or specifications. Makers don’t all measure it the same way, and options change it.
- The real thing: a public weighbridge. Weigh the vehicle loaded for a trip, with everyone in it, then with the trailer on. It costs little and replaces every estimate on this page.
Each axle and each tyre has a limit of its own too. A vehicle can be under GVM and still overload the rear axle, which is common with a heavy tow ball weight or a lot of gear behind the back wheels.
Common questions
What is GVM?
Gross Vehicle Mass is the most your vehicle is allowed to weigh fully loaded: the vehicle itself, fuel, people, accessories, everything you carry and the weight a trailer puts on the tow ball. The maker sets it and it is on the compliance plate.
What is payload?
Payload is GVM minus kerb weight: the weight you can add to the standard vehicle. Accessories such as a bull bar, drawers and a rooftop tent come out of it, as do passengers, water, extra fuel, gear and the tow ball weight of a trailer.
What is GCM?
Gross Combination Mass is the most your vehicle and trailer are allowed to weigh together. You can be under your GVM and under your towing capacity and still be over GCM, so check all three.
Does tow ball weight count towards GVM?
Yes. The weight the trailer puts on the tow ball is carried by the vehicle, so it uses up payload like any other load.
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