In this article we’re going to give a simple explanation of how to work out caravan towing weights:

How to work out how much weight you can carry in your caravan?

If your car’s towing capacity legally allows you to tow this weight?

**HINT**: You may not be able max out on your car’s and caravan’s legal weight at the same time

Let’s get started:

## First… Why Do You Need to Know How to Work Out Caravan Towing Weights?

As long as I don’t pack too much I should be okay, right? ATM, GVM, GCM. I don’t need to worry about that stuff, do I?

Well, you might be the best driver in the world. But…

…what happens when you are involved in an accident that you didn’t cause?

What if someone pulls out in front of you and you have to try to stop suddenly?

Or if you have to swerve to miss an unexpected obstacle and get the wobbles?

Or you’re just plain unlucky and get called in over a weighbridge?

If you couldn’t be bothered learning about this stuff, you may as well not bother with paying for your insurance premiums either then.

Having a basic understanding of vehicle and towing weight definitions is a must for safety, reduced wear and tear, and for your hip pocket.

It can become overwhelming, so for simplicity sake we’ll use some rounded numbers.

So if you’re wondering how to work out caravan towing weights the first definition to understand is a caravan’s starting point:

## What is TARE Weight of a Caravan?

When talking caravans, this is the weight when not carrying any load, ready for service, and **with all standard equipment and any options fitted**.

Note well the last part of the definition, “**and any options fitted**”.

This means the tare mass that is listed on your mass produced compliance plate may not reflect your true ‘base weight’. Even straight out of the showroom, you may find a variation between what you think your van weighs and what it shows on the local weighbridge.

For our example we’ll use our caravan, a Jayco Expanda, which is pretty much 2,000kg

The next key definition to understand is the caravan’s maximum weight:

**Your Caravan’s Maximum Weight is the Aggregate Trailer Mass (ATM) **

ATM is the total mass of the trailer when carrying the maximum load recommended by the manufacturer. This is the weight most people think about when talking towing capacity or how to work out caravan towing weights.

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Our caravan has an ATM of about 2,500kg.

So pretty much, the load capacity (or payload) you can carry is:

**Load Capacity = ATM – Tare**

This would give 2,500kg – 2,000kg = 500kg load capacity.

Right?

Well, that annex, gas, food, clothes, the water in the tanks (grey and potable) all start to add up pretty quickly.

Really, the only way you know whether or not you’re compliant is to take yourself over a weighbridge.

So, as long as you have a vehicle that’s rated for 2,500kg towing capacity and you don’t overfill the caravan you’re right now, yes?

Maybe.

Still need to consider the tow vehicle:

## What is TARE Weight of a Car?

Similar to the caravan definition, this is the mass of a vehicle, unoccupied and unladen, with all fluid reservoirs filled to nominal capacity except for fuel, which shall be 10 litres only, and with all standard equipment and any options fitted.

In this example we’ll use a car that conveniently has a Tare of 2,000kg.

Now we have the base weight of the vehicle, I’m sure you can guess where this is heading?

## Your Car’s Maximum Weight is Gross Vehicle Mass (GVM)

This is the maximum laden mass of a motor vehicle as specified by the ‘Manufacturer’.

This is pretty similar to Aggregate Trailer Mass, just on the tow vehicle side of things. Same way of working out the vehicles’ load capacity:

**Load Capacity = GVM – Tare**

If our fictional car had a max GVM of 3,000kg and a Tare of 2,000kg, that would leave us 1,000kg of load capacity… The loads that need to be taken into consideration here though include people, the rest of the fuel, things like roofracks and bumper bars, luggage, etc.

But wait, there’s more. The big one:

## The Maximum Total Weight for Your Car and Caravan is Gross Combined Mass (GCM)

**This is one of the most important things to consider in how to work out caravan towing weights**

This is the value specified for the vehicle by the ‘Manufacturer’ as being the maximum of the sum of the ‘Gross Vehicle Mass’ of the drawing vehicle plus the sum of the ‘Axle Loads’ of any vehicle capable of being drawn as a trailer (i.e. the max weight of both vehicle and manufacturer.

So, we might have a caravan with an Aggregrate Trailer Mass of 2,500kg, and a vehicle with a Gross Vehicle Mass of 3,000kg. We have a total of 5,500kg between the two.

Sounds good, as both the car and van aren’t overweight, right?

Well, the Gross Combined Mass may be less than this (e.g. 5,350k). So although neither of the elements are overweight, the combination may be.

A final point to make:

**Towball Download: You Caravan Loses Weight and Your Car Gains It**

Normally 10% of the trailer is transferred onto the tow vehicle.

[Not always the case though… read our article: How To Work Out Caravan or Camper Tow Ball Weight]

In this scenario, that’s 250kg extra that needs to be added up with the rest of the gear. If you were already maxed out with people and stuff, putting a trailer on may make the tow vehicle overweight. It’s a bonus for the trailer though, as weight comes off the tally (and hopefully ensures you’re below the Aggregate Trailer Mass)… which is:

**Gross Trailer Mass**

So when the trailer is couple to the towing vehicle, it’s given up the weight off the jockey wheel and instead the car is carrying it, this is known as Gross Trailer Mass (GTM)

It’s very easy to check your weights… you can get a ball weight scale from eBay for less than $50 with free postage:

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Or:

Most Popular Caravan Accessories for Travelling Australia [2019]

[Just don’t get too much stuff]

## Summary: How to Work Out Caravan Towing Weights

The amount you can put in your caravan is it’s max weight (ATM) minus it’s TARE (it’s base weight)

The amount you can put in your car is it’s max weight (GVM) minus its TARE (it’s base weight)

When you put the two together… you max not be able to max out on both

The references for these definitions are all from legislation and the ADRs. But hey, even though I used the textbook definitions, it’s my fault if I haven’t explained anything clearly so there’s still some confusion.

If that’s the case, please leave a comment, and I’ll go back to the drawing board.

I have gone cross eyed

Now colour blind and cross eyed? Simon, I don’t think you should be driving 😉

Thanks for great explanation.

Our pleasure Frank!

So I have a dmax with a gvm of 2950

I have a canopy and fridge and batteries added

So I recon my total vehicle weight including myself and my wife full tank of fuel would be 2850

Demax gcm is 5950

A caravan we are looking at buying has a atm 3080

Total that up is 5930

Because the atm is 3080 and they say to use 10 % for ball weight (300) but the caravan is listed as having 160 ball weight?

So even if the ball weight is 160 that would put my vehicle overweight 3010, is that a problem or do the scalies work on the overall

Which just under

I suppose my question is if you get pulled up by the scalies do they go on gcm or car and caravan separate

Hi Steve, you can get weighed as a combination AND the car/van individually

This pretty much means you might have to look at how your car is loaded and see if there’s 60Kg you can transfer to the van

This is a problem that commonly pops up… tow capacity may not always be able to be fully utilised when you’ve also got weight in the car

The 160 kg ball weight sounds pretty light for a van of ATM 3080 kg, it’s a touch over 5%. It’d be worth using some ball scales to check that

OK – I’m 74 and confused. My Lexus has a GVM of 3260 and my Jayco Silverline has ATM 3110. I weighed the car with the van attached to the tow ball – that weight was 3,300 so I take it I’m over by 40 kilos ? The van, attached to the towing vehicle but with all the van’s wheels on the weighbridge weighed 2,860. So am I legally under the 3110 ATM ? If I take 40 kilos out of the car and transfer it into the van am I now fully legal ?

Yes, sounds like you’re over in the car by 40 kg when the caravan is attached.

1. The 3,300 kg that your car weighed is with the car carrying some of the caravan’s weight (the tow ball download) which could be anywhere between 200-300 kg for a van of your size

2. The van’s ATM is measured when it’s unhitched. So without knowing how much your car was offloading from the van, it’s hard to know exactly. If it was only 200 kg towball weight you’d just scrape in… but if it’s 250 kg, then adding on the 40 kg from the car would put the van over too

3. Best thing to do would be (a) go back to the weighbridge and measure the car and van when they’re unhitched

(I’d probably get some towball scales too)

Thank you for your prompt reply, Steve. My ball weight is about 290, so the car, without ball weight is 3010 and, to my mind, quite legal. The Van, including ball weight is 3150, so overweight by 40k. What is confusing me is that we seem to be adding ball weight to both car and caravan. I can’t get my head around that – is that the way it is ? If that’s the way they work it out, it seems I’m 40k over with both car and van – total 80k ??

Hi Don, sounds right – things have weight limits when they’re isolated AND when they’re combined. By the looks of things your overweight in your van when it’s sitting there by itself (the ATM).

When you hook it up to the car, some of the van’s weight is transferred to the car… but that then makes the car overweight

I would have a look and see (a) if you can shed some kilos from your payload, or (b) if your van is pretty much close to it’s ATM when it has nothing in it (it’s TARE), it might be worth speaking to the dealer. Sometimes the weight that it comes to you is higher than the listed TARE… which happens more than you think

Cheers,

Michael

Thanks for your reply, Michael. I do believe the caravan Manufacturers ‘fiddle’ with the weights (ball weights, ATM weight, etc.) With both of my last two Jayco vans, (both have front kitchens) I have had new compliance plates issued as, even when empty, I just could not get the ball weight down to what was on the compliance plate. With my current Silverline, we are only carrying 20 litres of water, have cut back big time on what we carry and are still overweight. I have been told that included in your allowed payload is the water you carry, the gas bottles, bed mattress, solar panel, etc., so you end up being able to carry bugger all of your own stuff. It all seems ridiculous to me. Anyway, thanks again for your advice.

Don

I have a Mazda bt50 which has been upgraded by a qualified engineer and comes in at tare2250 and gvm3330and van that has been upgraded by the same engineer tare2060 gvm and I put it over the weigh ridge and came up with the following a

Weights total weight combined 5.9400 / ute3240kgs van2700 kts loaded my estimation is that I would have 250 kgsup my sleeve and 90 kgs up my sleeve for ute does this seem right also what would the ball weight be for this combination all walk has been done and passed by NSW Registration and is printed on my Rego papers Thanking for your time as I am in my late sevenths and seems confusing to me and I am trying to do the right thing Regards Ken

Hi Ken,

When you say that your ute’s weight is 3240 kgs is that with the van attached or unhitched? If that’s the weight with the van hitched up then yes, you have another 90 kg weight capacity. Which is pretty much one person and no passenger!

For your ball weight… an estimate is that it’s 10% of your van’s weight… but this would vary depending on how your van is loaded. I actually wrote this post here today to help you out: https://abigpeacheyadventure.com.au/tow-ball-weight/

Cheers,

Michael and Natalie

Hi Chief, picking up an old thread here, but would like your take on something. I have an NW Pajero. with a tow rating of 3t with a Tb weight of <180 or 2.5 t for over 180 kg tbw.

we have been away in the van previously, but i have just taken it over a weighbridge. and would like clarity on the following. weights came back as 2.85t for the car (inc tbw) and the van 2.35. do i include the tow ball weight in the van weight when i am looking at towing capacity (ie if i am limited to 2.5 t – is that with or without the tow ball weight – the scales have it as 2.36 hitched or 2.64 unhitched) this has a significant impact. i can redistribute some weight to bring the TBW down to 250kg, but want to ensure that i am not towing more than 2.5 t. my understanding is that weight (tbw ) becomes part of the tow vehicles axle loading and therefore GVM. what is your take?

Hi Shaun, towing capacity refers to Aggregate Trailer Mass (ATM)… so the weight of the caravan unhitched which here is 2.64t

So you might be able to move some weight from your van to your car (as long as you don’t exceed the car’s max weight (GVM) or the max gross combined weight (GCM)

Bear in mind – once you redistribute weight it will throw out the towball download calculations as this is entirely based on where you put the weight, not how much. There’s an article on here about that too if you’re interested

Cheers