What is the Aggregate Trailer Mass (ATM)?
Also called the Gross Trailer Mass, the ATM is the total weight (tare) plus the load capacity of the trailer or caravan. The requirements for registering a trailer or caravan will vary based on its type, it’s ATM or what it’s used for.
How do I find the ATM?
Sometimes the manufacturer’s plate is on your trailer or caravan and has the ATM. If you’re unsure, contact the manufacturer of your caravan or trailer or a signatory to VicRoads Vehicle Assessment Signatory Scheme (VASS).
You can also look at a list of public weighbridges (External link) from the National Measurement Institute for more information.
What trailer size can be registered?
Maximum dimension for light trailers
Height:
- 4.0 metres, or
- 4.3 metres on specified highways
- 4.6 metres for livestock, car carriers and some low profile semi trailers
Length:
- 12.5 metres (including the drawbar), or
- 13.7 metres for semi-trailers
Width
- 2.5 metres including guards, awnings or permanent fixtures
If the trailer has one axle group or single axle near the middle of its load carrying surface and connects to the vehicle towing it by a drawbar, the maximum rear overhang is the lesser of:
- the length of the load carrying area, or body, ahead of the rear overhang line and
- 3.7 metres.
See Vehicle Standards Bulletin 1 - Building Small Trailers (VSB1) (External link) for more information.

Can my trailer get an exemption from being registered?
If you’ve got a light trailer (other than a trailer specifically built to carry a boat) it will be exempt from registration in Victoria if it:
- weighs less (tare mass) than 200kg unladen
- isn’t wider than the towing vehicle
- is 3 metres or less in length, including the draw-bar
- isn’t used for business.
You can still choose to register your trailer if it’s exempt from registration. If it’s exempt and not registered, it needs to show the same registration number as the towing vehicle or you can buy an exempt trailer plate.
How to apply for registration
For light trailers
I have a light trailer with an ATM of 750 kg
You'll need to:
My trailer has an ATM over 750 kg’s but less than 4.5 tonnes
You'll need to:
For heavy trailers
I have a trailer with an ATM over 4.5 tonne
You’ll need to:
What if my trailer or caravan is imported?
You’ll need to:
Check registering an imported vehicle for more information.
What type of fees will I have to pay?
A card payment fee applies if you pay by VISA or Mastercard.