Towing Weight Checker

There are five numbers on a towing job and four limits, printed in three different places — the car's plate, the caravan's plate and the towbar. People check one of them and miss the one that bites. The gross train weight is the classic: a car rated to tow 1,800kg may not be rated to tow 1,800kg while itself fully loaded.

Car kerbweight, in kilograms

The car as it left the factory, from the handbook.

Car's maximum laden weight

From the car's plate — the car fully loaded.

Trailer or caravan, loaded

Its maximum technically permissible laden mass.

Car's towing limit

What the car is rated to tow, braked.

Gross train weight

Car and trailer together, from the plate. 0 if not stated.

Noseweight

What presses down on the towball, measured with a gauge.

Towball limit

Off the towbar's own plate, often lower than the car's.

77.8% of kerbweight — inside the 85% guideline

✓	The car's towing limit	1400kg of trailer against a 1800kg limit
✓	The towball's limit	85kg on the ball against a 100kg limit
✓	The gross train weight	2300kg of car plus 1400kg of trailer is 3700kg, against 3800kg
✓	Noseweight within the usual range	6.1% of the trailer's weight, against the 5 to 7% usually recommended

✓ The percentages come back out of the weights — 77.8% of the car's kerbweight, and 6.1% of the trailer on the ball
✓ Each limit is compared against the right number — 4 limits checked separately, so a pass on one does not hide a fail on another
✓ The gross train weight is the car and the trailer together — 2300kg of car plus 1400kg of trailer is 3700kg, against 3800kg
✓ Inside the 85 per cent guideline — 77.8% of kerbweight — the guideline is advice for a stable outfit, not a legal limit
✓ Every stated limit is met — the towbar, the car and the trailer all agree

This is arithmetic against the numbers you type. What you may legally tow also depends on your driving licence and where you are, which this cannot know.

What this generator does

Compares the trailer against the car's towing limit, the noseweight against the towbar's, the car and trailer together against the gross train weight, and the noseweight against the recommended range.

How to use this tool

Type the car's kerbweight and its maximum laden weight, both from the handbook or the plate.
Type the trailer's laden weight and what the car is rated to tow.
Add the gross train weight and the towball limit, which are the two people forget.
Read each limit separately — a pass on one does not cover the others.

Understanding the controls

Car kerbweight: The car as it left the factory, with fuel and no load. This is what the 85 per cent guideline is measured against.
Car's maximum laden weight: From the car's plate: the heaviest the car itself may be, loaded. Used with the trailer weight for the gross train weight.
Trailer or caravan, loaded: Its maximum technically permissible laden mass, from the caravan's plate — not its weight empty, which is what the brochure tends to show.
Car's towing limit: What the car is rated to tow with a braked trailer, from the handbook. This is only one of the four limits.
Gross train weight: Car and trailer together, from the car's plate. This is the limit that catches people out, and it is often lower than kerbweight plus towing limit. Zero if the plate does not state one.
Noseweight: What presses down on the towball, measured with a gauge rather than guessed. Too little makes an outfit unstable; too much overloads the towbar and the car's rear axle.
Towball limit: From the towbar's own plate. It is frequently lower than the car's rear axle allowance, and it is the number that governs.

Common use cases

Checking whether a car can legally and safely tow a particular caravan
Seeing whether the gross train weight rules out a full car and a full van
Working out the noseweight to aim for when loading
Comparing two tow cars against the same trailer
Understanding what the 85 per cent guideline actually measures

How this generator works

Each limit is compared against the weight it governs, and reported separately with the sum shown — because a single pass or fail hides which one was the problem. The trailer as a percentage of kerbweight gives the 85 per cent guideline, which is advice for a stable outfit rather than a legal limit, and the page says so. The noseweight is expressed as a percentage of the trailer's laden weight and checked against the five to seven per cent usually recommended. The gross train weight is computed as the car's maximum laden weight plus the trailer's, rather than the kerbweight plus the trailer, which is the version that usually passes when it should not.

Randomness and fairness

Nothing is random. The same weights always give the same answer.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

This is arithmetic against the numbers you type; what you may legally tow also depends on your driving licence and where you are.
The 85 per cent figure is guidance for stability, not law, and experienced drivers tow closer to 100.
Noseweight must be measured with a gauge; the figure on a specification sheet is a maximum, not a measurement.
Trailer plates state a maximum laden mass, which is what should be used here rather than the empty weight.

Privacy and your data

The weights are compared in your browser. Nothing about your car or trailer is transmitted or stored.