Tare Weight

Tare weight is the weight of the empty packaging a load travels in: a carton, a pallet, a drum or, most often in ocean freight, the container itself. It is the difference between gross weight and net weight. A 20′ dry container, for example, typically has a tare of around 2,250 kg, so a box loaded with 18,000 kg of packed cargo weighs roughly 20,250 kg on the scale.

Tare vs gross vs net weight

• Net weight: the goods alone, without packaging. For U.S. imports, CBP requires the commercial invoice to state quantities in the weights and measures of the shipping country or of the United States (19 CFR 141.86(a)(4))
• Gross weight: the goods plus cartons, pallets and other packing. The packing list gives both totals; the U.S. International Trade Administration describes it as listing the total net and gross weight in kilograms. Transport documents such as the bill of lading and air waybill work with gross weight, because that is what the carrier moves
• Tare: the packaging or equipment weight between the two. For a packed container, the figure the ship and the truck care about is cargo gross weight plus the container's tare
• Payload: the most cargo a container may carry, which is its maximum gross weight minus its tare

Where a container's tare is marked

ISO 6346 sets the identification and operational marks every container carries. Among them, the maximum gross mass and the tare mass must be marked on the box in characters at least 50 mm high, and the maximum gross mass must match the CSC safety-approval plate. The Bureau International des Containers (BIC), which administers owner codes, shows these marks on the door end alongside the maximum payload and cubic capacity. Tare varies by build, manufacturer and repair history, so the figure on your actual container governs, not a published average.

Typical figures

The site's container dimensions table uses these typical published values:

• 20′ general purpose: tare about 2,250 kg, maximum gross 30,480 kg, payload about 28,230 kg
• 40′ general purpose: tare about 3,750 kg, maximum gross 30,480 kg, payload about 26,730 kg
• 40′ high cube: tare about 3,940 kg, maximum gross 30,480 kg, payload about 26,540 kg

30,480 kg (about 67,197 lb) is a common rating for 20′ and 40′ dry boxes, but newer units are often rated higher; Hapag-Lloyd's container specification, for example, lists 20′ and 40′ general-purpose units at both 30,480 kg and 32,500 kg.

Tare and the VGM

Before a packed container is loaded on a ship, SOLAS regulation VI/2 requires the shipper to declare its verified gross mass. Under Method 2 the shipper weighs every package, pallet, piece of dunnage and securing material and adds the container's tare. Leaving the tare out, or declaring net weight instead of gross, under-declares the container by tonnes.

The road limit usually comes first

In the United States, the federal gross vehicle weight limit on the Interstate System is 80,000 pounds (23 CFR 658.17), and that total includes the tractor, the chassis, the container's tare and the cargo. States may issue special overweight permits for nondivisible loads, which federal rules define as loads that cannot be split without compromising their intended use, destroying their value or taking more than eight work hours to dismantle (23 CFR 658.5). A container of cartons can be split, and grandfathered state weight allowances (23 CFR 658.17(i)) vary by state and route, so do not count on a permit: a box loaded to its plate payload can be legal at sea and still too heavy to dray. Ask for the legal load at both ends before you stuff dense cargo.

Common mistakes

• Using the packing-list net weight where the gross weight is asked for
• Taking a tare from a generic table when the container's own marking differs
• Forgetting pallets, crates and bracing in the gross weight

On Airlift FCL shipments the shipper supplies the cargo weight and Airlift passes the VGM to the carrier. The container load calculator checks whether your cartons run out of space or weight first.