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, 8,000 kg of goods, 300 kg of pallets and packaging, 100 kg of securing materials and 150 kg of added fittings. Added contents total 8,550 kg. With the example tare of 2,350 kg, the combined estimate is 10,900 kg. The arithmetic remainder to 30,480 kg is 19,580 kg.

Those numbers are a hypothetical exercise. The 19,580 kg 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 collect it 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.

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 travelling by sea under the applicable SOLAS provisions, the shipper must provide verified gross mass through the required process. MCA guidance distinguishes weighing the packed container from an approved method that adds the contents and tare. The latter is not simply permission to submit the result from any online calculator.

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. 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 collection.
• Obtain separate confirmation of handling and transport arrangements.