VGM: How to Calculate Verified Gross Mass (Method 1 and 2)
· 5 min de leitura
To calculate VGM (verified gross mass), add the weight of the cargo, the packing and securing material, and the container's tare. That is SOLAS Method 2. Method 1 is to weigh the packed container and take off the truck and chassis. Either way, the shipper signs the result and sends it to the carrier before the VGM cut off, or the container is not loaded.
This guide explains both methods with worked numbers, what the VGM declaration must contain, who is responsible, and the checks that stop a container being rolled. You can do the sums and print the declaration with the free VGM calculator.
What is the verified gross mass (VGM)?
The verified gross mass is the total weight of a packed shipping container: the cargo, everything used to pack and secure it, and the empty container itself. Since 1 July 2016 the SOLAS convention (chapter VI, regulation 2) requires the shipper to give the carrier a verified weight for every packed container before it is loaded on a ship.
The rule exists because misdeclared container weights cause stack collapses, damaged ships and injured crew. The weight on the booking or bill of lading is not enough on its own: it must be a verified figure from one of the two methods below.
How to calculate VGM: Method 1 and Method 2
SOLAS allows two methods. Both must use calibrated and certified weighing equipment where weighing is involved.
| Method 1 | Method 2 | |
|---|---|---|
| What you do | Weigh the packed, sealed container | Weigh every package and add packing and tare |
| Formula | VGM = weighbridge reading minus truck and chassis | VGM = cargo + packing, pallets, dunnage and lashing + container tare |
| Equipment | Weighbridge or crane with load cells | Calibrated scales for the packages |
| Best for | Any cargo, including loose bulk | Cartons and pallets weighed before stuffing |
Method 2 is not allowed for loose bulk cargo such as scrap metal or unbagged grain, because it cannot be weighed piece by piece. Some countries also require shippers using Method 2 to have their process certified or approved, so check the rules of the country of loading.
Method 1 example
A truck with a loaded 20 ft container crosses a certified weighbridge and reads 32,600 kg. The tractor and chassis weigh 14,900 kg empty, with a full fuel tank.
- VGM = 32,600 kg minus 14,900 kg = 17,700 kg
Weigh the truck and chassis on the same weighbridge if you can. Using a figure from a spec sheet adds error, because fuel and equipment change the weight.
Method 2 example
You are loading a 40 ft high cube with 18,400 kg of cartons (from the calibrated scale readings on the packing list), 350 kg of pallets and dunnage, and the container has a tare of 3,900 kg on its CSC plate.
- VGM = 18,400 + 350 + 3,900 = 22,650 kg
The maximum gross mass on the CSC plate of a typical 40 ft high cube is 30,480 kg, so 7,830 kg of payload is left. Packing list weights only count if the packages were actually weighed: a carton weight estimated from a spec sheet is not a verified weight.
Where to find the container tare weight
The tare weight of the container is printed on the CSC safety approval plate and painted on the container door, along with the maximum gross mass. Use the figure on the actual container, not a typical value, because tares vary by maker and age.
Typical figures, for checking only:
| Container | Typical tare | Typical maximum gross |
|---|---|---|
| 20 ft dry | about 2,200 kg | 30,480 kg |
| 40 ft dry | about 3,750 kg | 30,480 kg |
| 40 ft high cube | about 3,900 kg | 30,480 kg |
Inside dimensions and door sizes are on the shipping container dimensions page.
The VGM declaration: what it must include
The VGM declaration is the signed statement of the container's weight. Carriers accept it on paper, as a PDF, through their booking portal or by EDI, but the content is the same:
- Container number
- Booking number
- The VGM, in kilograms
- The method used (1 or 2)
- The name of the shipper and of the person authorised to sign
- The date and the signature
The signature belongs to the shipper named on the bill of lading, or a person the shipper authorises, such as a freight forwarder acting for it. The calculator on TradingForms fills these fields and prints the declaration as a PDF or Excel file for your records.
Who is responsible for the VGM, and when is it due?
The shipper is responsible for the VGM, even when a forwarder or a packing warehouse does the weighing. The carrier and terminal use it for the stowage plan and must not load a container without one.
Each carrier sets a VGM cut off in the booking, usually some hours or a day before the vessel's cargo cut off. If the VGM arrives late or is missing, the container is held at the terminal and can miss the ship, with storage charges and a new booking on top. A VGM that differs a lot from the terminal's own weighing can also be refused.
US and Canada specifics
- United States: the US Coast Guard treats the VGM as a matter between the shipper and the carrier and has not set penalties of its own. Carriers and terminals apply the rule at the gate, so US exporters still need a VGM for every export container.
- Canada: Transport Canada applies the SOLAS VGM rule to containers loaded in Canadian ports and has published guidance for shippers, so check it if you use Method 2.
- Road limits: a container can be under its CSC maximum and still be too heavy for the road. In the US a typical truck, chassis and container must stay under 80,000 lb gross on the Interstate unless permitted. Check this before you stuff dense cargo, such as tiles or metal parts, into a 20 ft container.
Common VGM mistakes
- Leaving out packing material. Pallets, dunnage, airbags and lashing count. On a full container they can add several hundred kilograms.
- Using the booking weight. The weight given when you booked is an estimate. The VGM must come from Method 1 or Method 2.
- Using a typical tare. Read the CSC plate. A wrong tare puts the whole VGM out.
- Mixing pounds and kilograms. SOLAS asks for kilograms. If your scale reads pounds, convert (1 lb = 0.4536 kg) before you declare.
- Sending it after the cut off. Put the VGM cut off in your shipping checklist, next to the documents cut off for the commercial invoice and packing list.
Calculate your VGM now
Open the VGM calculator, choose Method 1 or Method 2, enter the weights in kg or lb and the CSC maximum, and print the declaration with your container, booking and seal numbers. Everything runs in your browser. The calculator is for estimates and paperwork: the figure you declare must come from calibrated, certified weighing.
Frequently asked questions
How do you calculate VGM?
Method 1: weigh the packed and sealed container on a certified weighbridge and take off the truck and chassis weight. Method 2: add the weighed cargo, the packing and securing material, and the container tare from the CSC plate.
Does VGM include the container tare weight?
Yes. The verified gross mass is the cargo, the packing and securing material, and the empty container's tare weight added together.
Who signs the VGM declaration?
The shipper named on the bill of lading, or a person the shipper authorises, such as its freight forwarder. The signature confirms the weight was obtained by Method 1 or Method 2.
What happens if the VGM is missing or late?
The carrier and terminal will not load the container on the ship. It stays at the terminal, can miss the vessel and may run up storage charges until a VGM is received.
Is VGM declared in kg or lb?
SOLAS asks for the verified gross mass in kilograms. If your scale reads pounds, convert to kilograms before you send the declaration (1 lb is 0.4536 kg).