Reading the V5C: the weight fields
16 Aug 2026 · by Jérémy Vaucher
The V5C logbook is the most poorly read document in the glovebox. People look for the registration and the date, then skip the column of figures in the middle. That is a shame, because everything you need to tow legally sits in a handful of coded fields: F.1, F.2, F.3, G, and where they appear, O.1 and O.2.
Here is how to read them, line by line, without the jargon.
Why those codes exist
Registration documents use harmonised European codes. Each letter maps to one precisely defined mass. That way a roadside check, an insurer or a caravan dealer can talk about exactly the same thing, whatever country the vehicle was registered in.
F.1: the technically permissible mass
This is the maximum laden mass the manufacturer considers technically acceptable. It is an engineering figure, derived from the running gear, the brakes and the structure. It can be higher than the value actually authorised for use, which is why the next field exists.
F.2: the gross vehicle weight you live with
F.2 is the maximum laden mass permitted in service in the country of registration, in other words the gross vehicle weight. Your car, with fuel, passengers, luggage and the noseweight of the caravan, must never exceed it.
It is also the figure that gives you real payload: gross vehicle weight minus kerbweight. Plenty of families discover at holiday loading time that the margin is thinner than expected, especially with a roof box and a caravan on the back.
F.3: the gross train weight, the ceiling for the outfit
F.3 states the maximum permissible laden mass of the whole combination in service, meaning the loaded car plus the loaded trailer. It is the global limit for your outfit.
Be aware that some documents leave this field blank depending on the vehicle and the model year. When that happens, fall back on the manufacturer plate and the handbook. What remains for the trailer is F.3 minus F.2, and it is often more restrictive than the headline towing figure. That is set out in gross vehicle weight and gross train weight.
G: kerbweight
G gives the mass of the vehicle in service, meaning the kerbweight with fluids and, depending on the definition used, the driver. It is the starting point for working out how much you can still load.
One important detail: the kerbweight of your particular car depends on its options. A sunroof, a spare wheel, upholstery, a factory fitted towbar, all of it weighs something and comes straight out of your payload. The brochure figure rarely describes the car sitting on your driveway.
O.1 and O.2: what you are allowed to tow
O.1 gives the braked towable mass, O.2 the unbraked towable mass. These are the two ceilings, depending on whether your trailer has its own braking system. The subject is covered in braked and unbraked towing weight.
Both figures belong to your vehicle with its equipment. That is exactly why they outrank any brochure, any forum thread and any over enthusiastic salesperson.
The sums in three lines
Once the fields are identified, the rest is mechanical.
- Car payload: F.2 minus G.
- Theoretical trailer allowance from the outfit: F.3 minus F.2.
- Real towing capacity: the lower of O.1 and the previous result.
That is precisely the method used on every page of this site, for instance on the Volkswagen Tiguan, the Renault Austral or the BMW X3, where the figures are broken down engine by engine.
The most common misreadings
- Confusing F.1 with F.2 and assuming you can load more than allowed.
- Using the brochure kerbweight instead of the one on your own paperwork.
- Forgetting that caravan noseweight sits on the car, so it eats into the gross vehicle weight.
- Ignoring F.3 because the headline towing figure looks generous enough.
- Trusting the paperwork of a supposedly identical car seen online, when options change the numbers.
And the trailer paperwork
Trailers have their own plated weights, and for caravans those figures carry names of their own. The maximum technically permissible laden mass is the ceiling you must not exceed loaded. The mass in running order is roughly what the caravan weighs as it left the factory with its standard equipment. The difference between the two is the user payload, meaning everything you are allowed to put inside.
That payload is smaller than most owners assume, and it disappears fast: awning, gas bottles, water, crockery, outdoor furniture, bikes. A caravan loaded beyond its own plated mass is just as illegal as an overloaded car, and it is far more common.
Where a trailer has no registration document, the manufacturer plate on the drawbar or chassis is the reference. It carries the same information, and at a roadside check it is what counts.
When the figures disagree
Brochure, vehicle plate and registration document do not always quote identical values. That is not necessarily an error: the brochure describes a representative version, the plate gives the technical masses of the vehicle, and the registration document records the values retained for use on the road.
The order of precedence is simple. To know what you are allowed to do, the paperwork for your own vehicle wins. To understand why a figure is lower than expected, manufacturer documentation explains the technical context. And where a significant gap remains unexplained, a franchised dealer can retrieve the exact approval figures from the vehicle identification number.
Worth remembering
The logbook is not just another piece of admin: it is the legal reference for your outfit. Five fields read properly beat an hour of forum scrolling. Once you have the figures, compare them with your exact engine on its page, or start from a ranking by capacity to spot the cars that cover your need. Always check the V5C logbook before towing.