VGM calculation, Method 2: how to work out a container’s verified gross mass

With Method 2, the verified gross mass (VGM) of a packed container is the gross mass of every package and cargo item, plus pallets, dunnage and securing material, plus the container’s tare mass. The shipper named on the bill of lading declares it, signed by a person it authorises, and without it the container is not loaded. The weighing method must be certified as decided by the State where the container was packed and sealed (IMO MSC.1/Circ.1475, §5.1.2.3); in Spain that means an ISO 9001 or equivalent certified quality system.

Calculate your VGM

With the illustrative example figures, three lines of goods add up to 18,320 kg (22.5 × 480 + 31 × 120 + 950 × 4). Twenty 25 kg pallets, 60 kg of dunnage and 35 kg of securing material add 595 kg. With a 2,230 kg tare, the VGM is 21,145 kg, 9,335 kg below the example maximum gross mass of 30,480 kg. The breakdown sheet at the bottom is ready to print.

What the VGM is and who declares it

Gross mass is the container’s tare mass plus the mass of all packages and cargo items, including pallets, dunnage and other packing and securing material packed into it. It becomes the verified gross mass when it is obtained by one of the two methods in the rules (MSC.1/Circ.1475, §2.1.6 and §2.1.16).

The requirement comes from the amendment to SOLAS regulation VI/2 adopted by the IMO Maritime Safety Committee at its 94th session (17 to 21 November 2014, resolution MSC.380(94)). It entered into force on 1 July 2016 (IMO). The common approach to applying it is in the guidelines MSC.1/Circ.1475 of 9 June 2014.

Obtaining and documenting the VGM is the shipper’s responsibility. The shipper is the legal entity or person named as shipper on the bill of lading, sea waybill or equivalent multimodal transport document, and/or the one who concluded the contract of carriage with the shipping company (§2.1.12 and §4.1). Who books the carriage follows from the sale contract; the guide to import documents by Incoterm covers what each side provides.

The document can be part of the shipping instructions or a separate communication. It is signed by a person authorised by the shipper, and the signature may be electronic or replaced by the name in capitals (§6.1 and §6.2).

Method 1 and Method 2

• Method 1: once packing and sealing are finished, weigh the packed container (or have a third party weigh it).
• Method 2: weigh all packages and cargo items, including pallets, dunnage and other packing and securing material, and add the tare mass of the container, using a certified method.

The circular adds two useful details (§5.1.2.1 and §5.1.2.2). Original sealed packages with their accurate mass clearly and permanently marked on them do not need to be weighed again. And cargo that does not lend itself to weighing item by item, such as scrap metal or unbagged grain, should go by Method 1. How the certification of Method 2 is done is up to the State concerned (§5.1.2.3.1).

If the container is weighed on a road vehicle, the tare of the vehicle and, where applicable, the tractor is subtracted, and so is the fuel in the tractor’s tank (§11.1).

The tare mass is marked on the container itself under the ISO 6346 marking standard, and the maximum gross mass is on its CSC Safety Approval Plate. A container above that maximum may not be loaded (§10.1 and §12.1). How many pallets fit in each container size is covered in the pallets per container guide.

When it has to be sent

Providing the VGM to the ship’s master or his representative and to the terminal representative, sufficiently in advance to be used in the ship stowage plan, is a condition for loading. Electronic means such as EDI are preferred, and the shipper can meet the obligation by sending it to the shipping company, which passes it to the terminal (§6.3 and §6.3.1).

SOLAS sets no fixed hour. In the circular’s words, there is no deadline other than arriving in time for the stowage plan, and the shipping company that holds the contract of carriage tells the shipper the specific cut-off after discussing it with the terminal (§6.3.2). That is why the cut-off differs between ports and carriers.

A container that reaches the terminal without a VGM should not be loaded until one is obtained. The master or the terminal may obtain it on the shipper’s behalf, weighing it in the terminal or elsewhere, and who pays for that, and for storage, demurrage or return, is a matter for the contracts between the parties (§13.1 and §15.2). Having a VGM is a prerequisite for loading, not an entitlement: the master keeps the final say (IMO).

Is there a tolerance?

The IMO guidelines give no figure. They say that a difference between the declared mass and the verified mass is resolved with the verified mass; that a difference between the shipper’s VGM and the terminal’s weighing is resolved with the terminal’s; and that enforcement falls to each government under national legislation (§9 and §15.1). So any tolerance is national, and it has to be checked in the country where the container is packed (inferred from §15.1).

Spain does write one down. The Spanish resolution of 15 June 2016 (twelfth section, point 3) treats as a discrepancy between two weighings:

• a difference of 500 kg, more or less, for containers loaded with up to 10 tonnes;
• a difference of 5%, more or less, for containers above 10 tonnes.

When there is a discrepancy, the verified mass prevails over the declared one, and the terminal’s weighing over the shipper’s. It is a rule for settling differences, not an allowance for estimating (inferred from how the section is written).

What Spain requires

The rule is the Resolution of 15 June 2016 of the Directorate General of the Merchant Navy (Dirección General de la Marina Mercante), published in the Spanish official journal, BOE no. 157, on 30 June 2016. It applies to packed containers shipped from 1 July 2016. On top of the IMO guidelines it sets:

• Scope. All CSC containers to be stowed on a ship subject to SOLAS chapter VI. It does not cover voyages entirely between Spanish ports, nor containers on a chassis or trailer driven on or off a ro-ro ship on short international voyages.
• Certified Method 2. The calculation must sit inside a quality management system certified to ISO 9001 or an equivalent standard, covering control and traceability of the weight of each item and calibration of the weighing equipment, certified by a body accredited by ENAC (the Spanish accreditation body) or recognised by it.
• Scales. Calibrated by a laboratory accredited or recognised by ENAC; equipment verified by Spain’s metrology control bodies is also valid.
• Minimum content of the document. Shipper’s name and address (and those of any third party verifying for it); the mass in kilograms preceded by the letters VGM; the method; name and signature of the issuer; date and place. Leaving out only the method or the date and place does not by itself stop loading.
• Responsible declaration. Stating the VGM implicitly declares that, if Method 2 was used, the system meets those requirements, and that the weighing equipment is identified and meets the calibration rules.
• Weighing in port. Inside the service area of a port of general interest, verifying the mass is a commercial service.

As of 11 October 2026 the BOE record lists no later act amending or repealing it.

Where Method 2 goes wrong

• The pallet counted twice. If the per-package gross mass on the packing list already includes the pallet, do not add it again.
• Net instead of gross. Method 2 adds packages with their packing; net weights come up short.
• A “typical” tare. The tare is that of the specific container, marked on it; another box of the same size may differ.
• Forgetting the securing material. Straps, chocks, airbags and dunnage are part of the gross mass.
• Cargo that cannot be weighed item by item. Scrap and bulk go by Method 1.
• Not reading the CSC plate. If the VGM is above the maximum gross mass, the container is not loaded.

There is more on loading and documenting containers in the guides index.

What HeavyDeals covers

In HeavyDeals, the export file of each order generates the packing list with net and gross weight per line, package counts and totals; and its container configurator shows the weight and pallets in each container against the limits the distributor sets. Those are the figures behind sections 1 and 2 of the calculator; the tare, the certified method and the signature stay outside. See how it works.

Every figure and rule was checked against the sources above, on the date shown next to each; last review of this guide: 11 October 2026. The examples use illustrative figures, not today’s quotes. This is not legal or tax advice. Written with the help of AI and reviewed by the HeavyDeals team.