What do GVM, GCM, ATM and GTM mean?
Short answer
GVM, GCM, ATM and GTM are maximum manufacturer or registration mass ratings for a vehicle, combination or trailer; they are ceilings, not the vehicle’s actual scale weight or an automatic legal loading entitlement.
Plain English
Gross Vehicle Mass (GVM) is the maximum loaded mass of a vehicle. Gross Combination Mass (GCM) is the maximum total loaded mass of a motor vehicle and the vehicles it may lawfully tow. Aggregate Trailer Mass (ATM) is the maximum loaded trailer mass when uncoupled, including the mass that would be imposed on the towing vehicle when coupled. Gross Trailer Mass (GTM) is the maximum mass transmitted to the ground through the trailer’s axles when coupled.
These ratings work alongside the statutory mass limits. The lawful mass is constrained by the lowest applicable manufacturer or registration rating, tyre and component rating, axle or axle-group limit, gross or axle-spacing limit, and any notice, permit or route condition.
What this means operationally
Record the ratings for every prime mover, rigid truck, trailer and coupling combination before allocating work. Compare the actual loaded masses with GVM, GCM, ATM, GTM, axle and axle-group limits, and do not assume a higher GML, HML or permit figure raises the manufacturer’s rating. Any re-rating must follow the applicable approved modification and registration process.
Who it applies to
Operators, drivers, loaders, schedulers, fleet managers, dealers, body builders, engineers and freight customers selecting or loading a heavy vehicle or combination.
Example
A combination may be below the statutory gross limit but still unlawful because the prime mover’s GCM, the trailer’s ATM or GTM, a coupling rating or an axle-group limit is lower.
Exceptions and traps
A lawful re-rating or approved modification can change a recorded rating, but a workshop opinion or replacement compliance plate is not enough by itself. Registration-authority decisions and vehicle-specific approvals must be checked. Western Australia and the Northern Territory use their own domestic mass and registration frameworks.
What changed
The 1 August 2026 increase to General Mass Limits did not automatically increase any vehicle’s GVM, GCM, ATM, GTM or component rating. The lowest applicable ceiling still controls.
Legal foundation
Heavy Vehicle National Law s 5 definitions of ATM, GCM, GVM and loaded mass; Heavy Vehicle (Mass, Dimension and Loading) National Regulation 2013 ss 6 and 8-10; applicable ADR and registration requirements
Sources & primary documents
- www.legislation.qld.gov.au/view/whole/html/inforce/current/act-2012-hvnlq
- www.legislation.qld.gov.au/view/whole/html/inforce/current/sl-2013-0077
- www.nhvr.gov.au/road-access/mass-and-dimension/mass-limits/manufacturers-mass-limits
- www.nhvr.gov.au/road-access/mass-and-dimension/trailer-types
- www.nhvr.gov.au/road-access/mass-and-dimension/mass-limits/general-mass-limits
WWTG verification: Queensland legislation, NHVR
Frequently asked questions
Is GVM the truck's actual weight?
No. GVM is its maximum loaded rating; actual loaded mass must be measured or reliably established.
What does GCM cover?
The total maximum loaded mass of the motor vehicle and the vehicles it may lawfully tow.
What is the difference between ATM and GTM?
ATM includes the trailer’s full loaded mass, including coupling load; GTM is the mass carried through the trailer axles when coupled.
Does a higher GML raise my GCM?
No. A statutory mass-limit change does not alter the vehicle’s manufacturer or registration rating.
Which mass figure controls?
The lowest applicable statutory, manufacturer, registration, tyre, component, axle, route or authority limit.