Vehicle weights in Great Britain: what GOV.UK means by unladen weight, maximum authorised mass and train weight
The weight words GOV.UK uses for vehicles and trailers, where the figures are shown on a truck, and how the licence categories use them for a pickup, a tipper or a chipper trailer.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. It explains terms from GOV.UK pages and does not say which licence a particular driver holds or needs. The class table for tree crews is on the guide to driving licence classes by country, and this page covers the words behind it.
The terms
| Term | What GOV.UK says it means |
|---|---|
| Unladen weight | The weight of the vehicle when it is not carrying passengers, goods or other items. It includes the body and all parts normally used with the vehicle or trailer on the road. It does not include fuel or the batteries in an electric vehicle, unless the vehicle is a mobility scooter or powered wheelchair |
| Mass in running order | The total weight of a vehicle empty and ready for the road. For cars, buses and lorries it includes the driver, the body and all parts normally used with the vehicle, plus essential fluids such as oil and a full tank of fuel |
| Maximum authorised mass (MAM) | The weight of a vehicle or trailer including the maximum load that can be carried safely on the road. GOV.UK says it is also known as gross vehicle weight (GVW) or permissible maximum weight |
| Gross train weight (GTW) | Sometimes called gross combination weight (GCW). The total weight of the tractor unit plus trailer plus load |
| Down-plating | Showing a lower weight on the vehicle's plate or sticker when the vehicle is unlikely to be used at its potential maximum weight |
The page also says the MAM is listed in the owner's manual and is normally shown on a plate or sticker fitted to the vehicle, and that the plate may show a gross train weight too. The mass in running order definition differs for motorbikes, mopeds and quad bikes, which is outside this page. See GOV.UK on vehicle weights explained. The page does not use the term kerb weight.
How the licence categories use them
GOV.UK's driving licence categories page says the weight of the vehicle can decide the category and points to the weights page for the definitions. For the vehicle classes a tree crew meets, it gives these figures, all stated as maximum authorised mass:
| Category | Vehicle weight as GOV.UK words it | Trailer |
|---|---|---|
| B, test passed on or after January 1, 1997 | Up to 3,500 kg for petrol and diesel vehicles, which includes hybrids; up to 4,250 kg for electric or hydrogen vehicles, zero emission only | MAM up to 3,500 kg; combined MAM of vehicle and trailer not above 7,000 kg |
| B, test passed before January 1, 1997 | Usually a vehicle and trailer combination up to 8,250 kg MAM, as GOV.UK words it | Included in that combination figure; a minibus with a trailer over 750 kg MAM is also allowed |
| BE | Category B vehicle, MAM 3,500 kg | Depends on the BE valid-from date: before January 19, 2013 any size within the vehicle's towing limits; on or after January 19, 2013 up to 3,500 kg MAM |
| C1 | Between 3,500 and 7,500 kg MAM | Up to 750 kg |
| C1E | C1 vehicles | Over 750 kg; combined MAM not above 12,000 kg |
| C | Over 3,500 kg | Up to 750 kg |
| CE | Category C vehicles | Over 750 kg |
The categories page also lists light four-wheeled vehicles by unladen weight: up to 400 kg unladen, or 550 kg if designed for carrying goods. It notes that categories differ in Northern Ireland. See GOV.UK on driving licence categories.
Towing with a car licence
The GOV.UK page on towing with a car says the towing allowance depends on when the licence was gained, and that the MAM of both vehicle and trailer is needed, shown on a plate or sticker. It says a licence gained from January 1, 1997 allows a trailer up to 3,500 kg MAM, known as category BE, and that DVLA adds category BE to a physical licence at renewal if it is missing. For combinations heavier than the licence allows, it names the C1+E route: a provisional licence for a medium-sized lorry and trailer, the lorry theory test and the C1+E driving test, with Driver CPC tests if driving the lorry is the main part of the job. After that, vehicles and trailers up to a combined 12,000 kg MAM. See GOV.UK on towing weight limits with a car.
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