What Is VGM? | Verified Gross Mass Guide

Q: What happens if a container is loaded without a VGM declaration?

Under SOLAS, the master of the vessel and the terminal operator are both prohibited from loading a packed container onto a ship if a timely, signed VGM declaration has not been received. The container will be denied loading, potentially disrupting the entire supply chain for that shipment — resulting in missed vessel sailings, demurrage charges at the terminal, and contractual penalties under the sale and carriage contracts. In practice, most terminals and carriers enforce VGM requirements strictly, and shippers have built VGM submission into their standard documentation workflows.

What Is VGM (Verified Gross Mass)?

Verified Gross Mass (VGM) is the total weight of a packed freight container, determined and declared by the shipper with a level of accuracy and documentation that satisfies the mandatory safety requirements of SOLAS Chapter VI Regulation 2. The VGM encompasses every component of the loaded container: the cargo itself, the tare (empty) weight of the container, all packing and securing materials including pallets, and all dunnage — any material used to brace, block, or protect the cargo inside the container. This comprehensive weight figure must be obtained using one of two IMO-approved methods, must be communicated in a signed document (either electronically or on paper) to the shipping line and the terminal operator, and must be received sufficiently in advance of vessel loading to allow the preparation of an accurate stowage plan. The requirement applies globally to every packed container carried on a ship subject to SOLAS, with no de minimis exception for low-weight or low-volume shipments.

How VGM Works

The VGM determination process follows one of two methodologies specified in the IMO Guidelines Regarding the Verified Gross Mass of a Container Carrying Cargo (MSC.1/Circ.1475). Under Method 1, the shipper weighs the entire packed and sealed container using weighing equipment that is calibrated and certified to the accuracy standards of the national authority in whose jurisdiction the weighing takes place. This typically involves driving the container over a weighbridge (static or in-motion), lifting it with a twistlock-integrated spreader scale, or placing it on a container weigh pad — all of which capture the complete gross mass in a single measurement that is independent of the nature, configuration, or packing of the cargo inside.

Under Method 2, the shipper weighs every individual item placed in the container — each pallet, crate, carton, and piece of dunnage — using certified scales, sums these component weights, and adds the tare weight of the container as marked on the container's CSC safety approval plate. Method 2 requires meticulous documentation, as the shipper must demonstrate that every component was weighed on certified equipment and that the summation and calculation were correctly performed. Most regulatory authorities and industry bodies recommend Method 1 wherever practicable, as it eliminates the risk of cumulative weighing errors, omitted items, and mathematical mistakes inherent in the additive Method 2 approach. Regardless of the method chosen, the shipper must transmit the VGM in a signed communication containing the container number, the verified gross mass, the date of verification, and the identity of the authorized signatory.

Why VGM Matters for Maritime Safety and Supply Chains

The VGM requirement addresses one of the most persistent and dangerous information asymmetries in containerized shipping. Before 2016, cargo weight on a bill of lading was often a shipper-estimated figure, and industry studies repeatedly found that 10–20% of container weight declarations were inaccurate by more than 10% — with some containers exceeding their declared weight by 30 tonnes or more. Misdeclared container weights create a cascade of safety risks: overweight containers placed in upper tiers of a container stack can exceed the stack load limits of the cell guides and lashing systems, leading to stack collapses that endanger crew, longshore workers, and terminal personnel. Incorrect weight data corrupts vessel stowage planning software, which calculates stability, trim, bending moments, and stack loads based on declared weights — erroneous inputs can produce a stowage plan that renders the vessel unstable or overstressed in heavy weather. The World Shipping Council estimates that on average 1,382 containers are lost at sea annually, with stack collapses caused partly by misdeclared weights being a significant contributing factor. Since VGM enforcement began in 2016, misdeclaration rates have declined substantially — and the VGM document has become an essential element of the cargo documentation package, required alongside the bill of lading, packing list, and dangerous goods declaration for every container shipment.

Technology and VGM Compliance

The VGM requirement has accelerated the adoption of precision container weighing technology across the global supply chain. Modern weighbridge systems integrate with terminal operating systems (TOS) to automatically capture container numbers (via OCR cameras), record tare weights, calculate gross mass, and transmit VGM declarations electronically to carriers — eliminating manual data entry that is the primary source of VGM documentation errors. GOTEC's intelligent container weighing solutions incorporate AI-based container number recognition, automated weight capture with sub-100 kg accuracy, and direct electronic data interchange (EDI) connections to major shipping line systems using the VERMAS (Verified Gross Mass) message format. These integrated systems ensure that the VGM arrives at the carrier and terminal in time for stowage planning — typically at least 24 hours before vessel arrival at the load port — and that every container on the terminal has a matched, verified VGM before the stowage plan is finalized. The result is a safer, more efficient loading process that protects crew, cargo, and port infrastructure.

Frequently Asked Questions

What are the two approved methods for obtaining a VGM?

Method 1 requires weighing the entire packed container on calibrated and certified weighing equipment after the container has been packed and sealed. This method captures the total gross mass in a single measurement and is the approach preferred by most regulators and industry bodies. Method 2 involves weighing all cargo items, packaging materials, dunnage, and securing materials individually on certified scales, then adding those component weights to the container's tare weight as marked on its CSC plate. Method 2 requires documented, certified weighing of every individual item placed in the container and is subject to closer regulatory scrutiny — the shipper must be able to demonstrate the weight of every component if audited.

What happens if a container is loaded without a VGM declaration?

Under SOLAS Chapter VI Regulation 2, both the master of the vessel and the terminal operator are prohibited from loading a packed container onto a ship if a timely, signed VGM declaration has not been received. The container will be denied vessel loading — it remains on the terminal, potentially missing its intended sailing. The consequences cascade quickly: the shipper faces demurrage charges for the container sitting at the terminal, detention charges from the shipping line, possible contractual penalties under the sale contract for late delivery, and costs associated with rebooking the cargo onto a subsequent vessel. In practice, most terminals and carriers enforce the VGM requirement strictly, and most shippers have integrated VGM submission into their standard shipping documentation workflow to avoid these disruptions.

Related Terms

SOLAS — The International Convention for the Safety of Life at Sea, the parent treaty under which the VGM requirement was enacted in Chapter VI Regulation 2.
Container Weighing — The practical methods and equipment used to determine container weight; VGM is the regulatory requirement, while container weighing is the operational process.
Bill of Lading — The transport document that records cargo weight; VGM data must be consistent with the weight declared on the bill of lading but is a separate regulatory requirement.
TEU (Twenty-foot Equivalent Unit) — The standard unit of container capacity measurement; VGM declarations apply to individual containers regardless of their TEU size classification.