SOLAS VGM Calculator — Verified Gross Mass
Work out the verified gross mass of a packed container by either of the two methods SOLAS permits, check it against the container's maximum gross mass, and print a declaration summary for your carrier. Everything runs in your browser — nothing is uploaded.
| Item | Unit kg | Qty | Subtotal | |
|---|---|---|---|---|
| Cargo & packing total | 0 | |||
Include everything that goes inside: the goods, their packaging, pallets and slip-sheets, dunnage, lashing, bracing and any bags of desiccant. Method 2 requires all of it — the commonest cause of an understated VGM is forgetting the pallets.
Method 1 is weighing the packed and sealed container itself on calibrated and certified equipment. If the weighbridge ticket covers the whole vehicle, subtract the tractor and chassis so that only the container remains.
This is a working summary of the figures you entered, to help you complete your carrier's own VGM submission. It is not a legal form and has no standing on its own. Submit the VGM through the channel and by the cut-off your carrier specifies, signed by a person your company has authorised.
What VGM is, and why a container without one does not sail
Verified Gross Mass is the total weight of a packed container: the cargo, everything used to pack and secure it, and the empty container itself. Since the SOLAS amendments took effect on 1 July 2016, the shipper named on the ocean bill of lading must determine that figure and pass it to the carrier and the terminal in time for it to be used in the ship's stowage plan. The rule is short and unforgiving: a packed container without a verified gross mass must not be loaded onto the vessel.
The requirement exists because mis-declared container weights have contributed to stack collapses, lost boxes and structural damage to ships. A planner who believes a container weighs eighteen tonnes will place it high in the stack; if it actually weighs twenty-eight, the whole tier is loaded on assumptions that are wrong.
Pack and seal the container, then weigh the whole thing on calibrated and certified equipment. If the container is weighed on a vehicle, deduct the tractor and chassis so only the container remains. Simple, hard to argue with, and the only method open to you for unpackaged bulk cargo.
Weigh every package and cargo item, add all dunnage, pallets, packing and securing material, then add the container's tare mass from its CSC plate. The method must be certified or approved by the competent authority of the country where packing was completed, so it is not simply a matter of doing the arithmetic.
Where shippers actually get this wrong
Twenty standard wooden pallets can add several hundred kilograms. Lashing, bracing timber, airbags and slip-sheets add more. Under Method 2 every one of them belongs in the total; leaving them out is the single most common source of an understated VGM.
Tare varies with the build and with repairs over the container's life. A "typical" 40-foot tare taken from a reference chart can be off by more than a hundred kilograms against the box standing in your yard. The stencilled figure on the door is the one that counts.
Net weight is the goods alone. Payload is what the container may carry, that is maximum gross mass minus tare. VGM is the gross figure including the container. Putting a net weight where the carrier asked for VGM understates by the whole tare.
The VGM has to reach the carrier early enough to be used in stowage planning, and each carrier and terminal sets its own deadline ahead of vessel cut-off. A correct VGM submitted late can still leave your container on the quay.
Some national administrations allow a margin between the declared and the weighed figure, and some do not. The margin, where it exists, is set by the country in which the container is packed, not by the carrier and not by custom. Check your own administration's guidance rather than relying on a number a forwarder quotes from another jurisdiction.
Maximum gross mass and road limits are two different ceilings
The calculator warns you when the VGM exceeds the container's own maximum gross mass, which for most modern dry boxes is 30,480 kg. Clearing that ceiling does not mean the container can travel: road weight limits apply to the whole vehicle combination and are usually reached well before the container is structurally full, particularly on a single-drive tractor. A 20-foot container loaded with dense cargo often hits a road limit at a figure the box itself would carry easily. Check both before you commit to a loading plan.
- Check the container number before you declare it: the ISO 6346 Validator.
- Full specifications, tare ranges and payloads: the Container Standards Library.
- Work out how much fits before you work out what it weighs: the 3D Container Stuffing Calculator and the 3D Pallet Calculator.
- Weight drives freight, so it drives your costing too: the Landed Cost Estimator.
Frequently asked questions
The shipper named on the ocean bill of lading carries the obligation. A forwarder can weigh, calculate and submit on your behalf, and many do, but naming a forwarder does not move the responsibility off the party named as shipper on the bill.
No. Method 2 cannot be used for unpackaged cargo carried in bulk, and it must be certified or approved by the competent authority of the country where the container was packed. If your national administration has not approved your procedure, Method 1 is the route open to you.
Practice varies by port. A small difference may pass without comment where the national administration allows a margin; a large one typically means the terminal's figure is used, a weighing charge is raised, and the container may be held while the discrepancy is resolved. Repeated mis-declaration can attract penalties from the flag or port State.
The obligation attaches to the packed container, so for LCL the party who packs and ships the consolidated container — usually the consolidator named as shipper on the ocean bill — declares the VGM for the whole box. You still need to give them an accurate weight for your own consignment, because their figure is built from yours.
No. It is a free independent calculator written by IMPUTIX that follows the publicly documented structure of the two SOLAS methods. It is not published, endorsed or approved by the IMO, by any national administration or by any carrier, and using it does not constitute the certified Method 2 procedure. Declare through your carrier's own channel.
Reference information for planning purposes only, and not legal or regulatory advice. Requirements are set by SOLAS as implemented by the administration of the country where your container is packed; your carrier's and terminal's own procedures and cut-offs govern.