Shipping container weight: tare, contents and loaded mass

Read the three different weight figures

Tare is the empty container mass recorded for that unit. Maximum gross mass is the marked limit for container and contents together. The difference is the nominal payload allowance, but a particular load may face tighter restrictions from the floor, distribution, vehicle or lifting operation.

Fleet tables are useful for comparing formats, not identifying the unit that will arrive. Ask for a legible photograph of the actual markings and plate, the container identification, and an explanation of any modifications. If the unit has acquired a lining or fixed equipment since its tare was recorded, establish whether those additions are already included before calculating again.

Build the mass record without double counting

Decide whether your goods figure is a net product mass or an already packed mass. A delivery note for a loaded pallet may include its timber and wrapping. If that is the value you enter under goods, do not add the same pallet again under packaging. Label the basis in your project notes so the supplier can follow it.

Record how each figure was obtained: an actual weighing, a product specification, an estimate or an unknown. The calculator deliberately needs an explicit value for every category. A blank securing-material field must not silently become zero. Where the final packing materials are not selected, keep the calculation unfinished and ask who will supply their mass.

• Goods: total for all items and quantities, on a clearly stated net or packed basis.
• Pallets and packaging: anything not already counted in the goods figure.
• Dunnage and securing: timber, blocking, bracing and other added securing materials.
• Additional fittings: racking, lining or equipment not included in the current tare.
• Container: actual tare and maximum gross, with the unit identified.

A worked estimate and what it does not establish

Assume the 20ft fleet example above, 17,637 lb of goods, 661.4 lb of pallets and packaging, 220.5 lb of securing materials and 330.7 lb of added fittings. Added contents total 18,849.5 lb. With the example tare of 5,180.9 lb, the combined estimate is 24,030.4 lb. The arithmetic remainder to 67,196.9 lb is 43,166.5 lb.

Those numbers are a hypothetical exercise. The 43,166.5 lb remainder is not permission to add that much cargo. A heavy machine on a small support area can create a floor problem while the total mass remains below the gross limit. Its position can also matter to handling. Give the supplier the support footprint, load position and mass of the heaviest item instead of sending only the total.

Check item dimensions and the door →Record a mixed-item inventory →

Tell the transporter whether the container will be empty

A quote to deliver an empty container should not be treated as a quote to pick it up later while loaded. State the expected condition at each movement and who will remove the contents. If a loaded move is proposed, the transporter needs its own assessment of the unit, lifting arrangement, vehicle, route and site.

For Canadian road movements, the carrier must also assess vehicle and axle loads, dimensions, route permits, load securement and seasonal restrictions under the applicable provincial or territorial rules. The container’s marked gross mass is not the legal carrying allowance for every truck or route. At the installation point, describe the ground, supports, access and any changes in level. Dividing total mass by four does not establish that four improvised supports or the ground beneath them are suitable. Ask who is responsible for assessing and preparing the site, and keep that scope in the written quote.

Prepare delivery and unloading →

For sea freight, an estimate is not verified gross mass

For packed containers subject to SOLAS VI/2 and loaded onto a ship in Canadian waters, Transport Canada’s TP 15330 sets out the Canadian verified gross mass (VGM) procedure. The shipper either weighs the packed container or weighs the cargo, packaging, dunnage and securing materials and adds the container tare. The weighing equipment and method must meet that procedure; an estimate from this calculator is not a verified measurement.

This tool records a planning estimate. It neither verifies weighing equipment nor approves a method, signs shipping documentation or checks carrier deadlines. If your project includes sea transport, arrange the VGM process with the relevant shipper and carrier separately. The shipper must provide the signed VGM information in time for the carrier and terminal to use it in the stowage plan. Do not confuse that shipping requirement with ordering an empty box for static storage.

Send a weight brief the supplier can review

Keep the calculation, unit identity and open questions together. The tool can copy or download a text record and place a short summary in an editable quote request. State explicitly if you used the fleet example rather than the unit offered for sale.

Before accepting a proposal, reconcile any different tare, goods basis or included fittings. Ask for a revised calculation when the selected container or packing list changes. Keep the measured dimensions and the mass record linked to the same version of the project.

• Identify the container and whether its figures are confirmed or provisional.
• State each load category and any mass still requiring verification.
• Describe the heaviest individual load and how it contacts the floor.
• Distinguish delivery, installation, subsequent relocation and pickup.
• Obtain separate confirmation of handling and transport arrangements.