By Luis Lopez, AI transportation consultant, CEO of Go Hub.io Holdings Corp and subsidiaries, and host of the Freight Guru Podcast
Every packed export container that is loaded onto an ocean vessel needs a verified gross mass, usually called the VGM. It is one of the simplest data points in an export shipment and one of the easiest to get wrong. A missing or late VGM can keep a container off the vessel it was booked on, even when everything else about the shipment is ready.
This article explains what VGM is, who is responsible for it, the two methods allowed for determining it, and the practical habits that keep exporters out of trouble.
What VGM Means
The verified gross mass is the total weight of a packed container. It includes the cargo, all packaging and dunnage, pallets, bracing and securing materials, and the container itself. It is not the cargo weight alone, and it is not an estimate.
The requirement comes from the International Convention for the Safety of Life at Sea, known as SOLAS. Under SOLAS, a packed export container must have a verified gross mass before it is loaded on the vessel. The purpose is safety. Vessel stowage plans depend on accurate container weights, and misdeclared weights create risks for ship stability, stack loads, lifting equipment and the people who handle containers.
Who Is Responsible for the VGM
Under SOLAS, the responsibility belongs to the shipper named on the ocean bill of lading. That is true even when another party physically packs or weighs the container.
In practice, the work is often shared:
- A warehouse or packing facility may load and weigh the container.
- A forwarder or agent may transmit the VGM to the ocean carrier.
- A trucker may pull the container across a certified scale.
None of that shifts the underlying obligation. If you are the shipper on the bill of lading, you should know who is producing your VGM, how they are doing it, and how it is being submitted. Confirm that the party named as shipper on the booking is the party you expect. Our guide to house vs master bills of lading explains why the shipper named on each document can differ.
Method 1 and Method 2
SOLAS allows two methods for determining VGM.
Method 1: weigh the packed container
The container is packed and sealed, then the entire unit is weighed using calibrated and certified equipment. This is often done on a truck scale. The weight of the truck and chassis must be removed from the reading to arrive at the container’s gross mass.
Method 1 is straightforward when a certified scale is close to the packing site or on the route to the port. Its weakness is the arithmetic. If the tractor and chassis weights are not accurately known, the VGM will be off.
Method 2: weigh all contents and add the tare
Under Method 2, the shipper weighs all packages and cargo items, including pallets, dunnage and securing material, and adds the container’s tare weight. The tare weight is printed on the container door.
Method 2 works well when cargo is already weighed as part of the shipper’s process, such as packaged goods with known weights. It depends on a disciplined, documented weighing process. Rules about which shippers can use Method 2, and what certification or approval they need, can vary by country, so exporters should check the requirements that apply at the port of loading.
Submitting the VGM Before the Cutoff
The VGM must be submitted to the ocean carrier, and in many cases the terminal, before the VGM cutoff for the vessel. The cutoff is set by the carrier or terminal and is usually separate from the cargo cutoff, which is the last time the container can be gated in.
The VGM submission typically includes:
- The container number.
- The verified gross mass and the unit of measure.
- The method used.
- The name of the person authorized to sign on behalf of the shipper.
- The booking number or other reference.
Submissions can be made through the carrier’s systems, through electronic data exchange, or through a forwarder. Whatever the channel, confirm the submission was received and matched to the correct container and booking.
What Happens Without a VGM
Without a VGM, the container should not be loaded on the vessel. In practice, that means the container may roll to a later sailing. That creates delay and may bring additional costs, such as storage at the terminal, rebooking charges, and in some cases demurrage or detention. Our guide on demurrage vs detention explains how those charges work.
How VGM Relates to Road Weight Limits
The VGM addresses vessel safety. Road weight is a separate issue. A container can be within the ocean carrier’s and the container’s maximum gross weight and still be too heavy to move legally on the highway with a standard tractor and chassis.
Road limits depend on the gross vehicle weight, axle weights and axle spacing, and they vary by state and permit. A container that is acceptable at the vessel may still require a special chassis, a permit or a lighter load to reach the port legally. Exporters should plan packing with both in mind. For a regional example, see our article on Florida overweight container permits and triaxle chassis limits.
Overweight Risk
An overweight container is a problem at every step. It can strain chassis and lifting equipment, lead to fines on the road, and be refused at the terminal. Container weight limits differ by container type and size, so exporters should check the maximum gross weight shown on the specific container, not assume a figure. Our guide to container sizes covers the basics of container types.
Record Keeping
Keep records of how each VGM was determined. That includes:
- Scale tickets for Method 1, including truck and chassis weights used in the calculation.
- Weight lists for Method 2, showing how each cargo item, packaging and securing material was weighed.
- The container tare weight used.
- Calibration and certification details for the scales.
- Submission confirmations from the carrier or forwarder.
Good records protect the shipper if a weight is questioned later.
Common VGM Errors
- Submitting cargo weight instead of gross mass: leaving out the tare or packaging.
- Using estimated weights: estimates are not verified mass.
- Wrong container number: a transposed digit links the VGM to the wrong box.
- Units confusion: mixing kilograms and pounds.
- Late submission: missing the VGM cutoff while waiting for a scale ticket.
- Forgetting truck and chassis weight: a Method 1 calculation that does not subtract the equipment.
- Using an uncertified scale: weights from equipment that does not meet local requirements.
As an AI transportation consultant, the first thing I look at in an export workflow is whether the VGM is checked automatically against the booking before it is sent. Simple rules catch most mistakes: does the container number match the booking, is the weight within a reasonable range for the container type, is the unit consistent, and has the submission been confirmed before the cutoff.
Bottom Line
VGM is a small step with a big consequence. Know who is responsible, choose the method that fits your operation, submit before the cutoff, plan around road weight limits, and keep records. A disciplined VGM process keeps containers on the vessel they were booked on.
For more conversations on freight and AI, subscribe to the Freight Guru Podcast.
About the author: Luis Lopez is a Miami-based AI transportation consultant and logistics entrepreneur, the CEO of Go Hub.io Holdings Corp and subsidiaries, and host of the Freight Guru Podcast.
