How Much Copper Fits in a 20ft and 40ft Container? Tonnes by Grade, Form and Weight Limit

A 20ft container holds about 33 cubic metres. Filled to the roof with solid copper it would weigh close to 300 tonnes, so nobody ever fills one. Copper loads are governed by weight, not space: a 20ft box reaches its legal payload at 22 to 24 metric tonnes with most of the floor still visible. The exceptions are the bulky forms, loose wire, turnings and insulated cable, where the box fills up first. This guide gives typical tonnes per container for each grade we ship, and explains the three limits that set them.

Typical tonnes per container, by grade and form

The figures below are what we plan against for shipments out of Port Everglades. They assume standard dry containers, certified weights at the load port and the packing shown. Your destination may impose a lower ceiling; see the road-limit section further down.

Two patterns are worth noticing. First, everything dense converges on the same number, because the number is a legal limit rather than a property of copper. Second, a 40ft box adds only three or four tonnes over a 20ft for dense forms, while doubling the freight and handling cost per box. That is why most cathode, ingot and baled wire moves in 20ft containers, and why the 40ft is the right choice mainly for loose wire, turnings and cable.

Limit one: the container's payload rating

Every ISO container carries a maximum gross weight on its door plate, most commonly 30,480 kg for both 20ft and 40ft dry boxes, with some 40ft units rated to 32,500 kg. Subtract the tare, roughly 2.2 to 2.3 tonnes for a 20ft and 3.7 to 3.9 tonnes for a 40ft, and the payload comes out near 28 tonnes for a 20ft and 26.5 to 28.5 tonnes for a 40ft. Note the direction of that difference: the bigger box has a slightly smaller payload, because its own steel weighs more.

Nobody loads to the plate. Carriers, terminals and the road legs on both sides all impose lower ceilings, which is why the planning figures above sit several tonnes under the rating.

Limit two: road weight rules at each end

The container has to get from the yard to the ship, and from the discharge port to the buyer's plant, on a truck. Road limits are usually the binding constraint.

• Origin, Doral to Port Everglades. The US federal gross vehicle limit of 80,000 lb leaves a road-legal cargo weight of roughly 20 tonnes in a 20ft box once the tractor, chassis and container tare are counted. Florida issues overweight permits for sealed ocean containers on designated port routes, and our drayage is a short, permitted run. That is what makes 22 to 24 tonnes practical out of Port Everglades. Without a permit, plan on about 20 tonnes.
• Destination. This is the one buyers forget. Many countries cap a laden 20ft at 20 to 22 tonnes for inland haulage, and some inland corridors are lower again. If your plant is 300 km from the port, the legal weight on that road, not the container plate, sets the order. Tell us the discharge port and inland destination and we load to the lower of the two limits.

Limit three: Verified Gross Mass

Since July 2016 the SOLAS convention has required a Verified Gross Mass for every packed container before it is loaded on a vessel. The shipper is responsible for it, and the normal method is a certified weighbridge ticket for the sealed container. No VGM, no loading. We weigh each container after sealing, submit VGM to the carrier, and the same ticket becomes the certified weight on the packing list and the basis for the invoice weight. If your contract calls for a third-party inspector, the inspector witnesses the weighing and the figure appears on their report too.

Why form changes the number

Solid copper has a density of about 8.9 tonnes per cubic metre. Nothing we ship is solid; the useful figure is bulk density, the weight of a cubic metre of the material as packed, air included.

• Cathode stacks flat with almost no air. A bundle of plates is close to solid metal, so two dozen tonnes take up a strip down the middle of the floor. The load is blocked and braced to stop it shifting, and weight is spread across the floor rather than concentrated at one end.
• Ingot behaves like cathode on pallets. Pallet weight is set so the forklift can handle it and the floor loading stays even.
• Baled wire is the reason baling exists. A compact bale of mill berry can approach 3 tonnes per cubic metre; loose coils of the same wire run nearer 1.5 to 2. Baling can add four or five tonnes to a 20ft load and turn a volume-limited box into a weight-limited one.
• Turnings and chips are the lightest, often under 1.5 tonnes per cubic metre, and they carry moisture and cutting fluid that counts as weight but not as copper. They are usually shipped in big bags and priced on a dry, assayed basis.
• Insulated cable is mostly plastic by volume. A container of ICW fills up at 15 to 19 tonnes, and the copper inside is a recovery percentage of that, which is why ICW is priced the way it is.

Mixed grades in one container

A first export order often mixes grades so a buyer can evaluate several at once. That is fine, with three conditions: the grades are physically separated, each is bagged, baled or bundled so it can be identified, and the packing list shows the weight of each. The inspection report should record each grade on its own line. Mixing loose grades on the floor of one box turns the whole load into the lowest grade at the destination, because nobody can separate it again.

What the minimum order looks like on the ground

Our minimum export order is five 20ft containers. Using the planning table, that is roughly 110 to 120 tonnes of cathode, ingot or baled wire, and somewhat less for loose or bulky forms. Five boxes is the point where an ocean booking, an inspection visit and a set of export documents cost a sensible fraction of the cargo value. The export buying guide walks through what happens from confirmed order to vessel; typical lead time from a confirmed order to loading is three to seven days.

A planning worksheet

To size an order, work through these in sequence:

• Grade and packing. Pick the row in the table above.
• Destination road limit. Get the legal laden weight for a 20ft on the inland route from your haulier. Take the lower of that and the table figure.
• Box type. Dense form: 20ft. Loose wire, turnings or ICW: consider 40ft and check the destination handles it.
• Tonnage and tolerance. Multiply by container count, state the tolerance, and put both on the pro forma.
• Weight basis. Name which certified weight governs the invoice and who witnesses it.

Send us those five answers and we can quote per container, per tonne and per shipment, with the freight and inspection estimate alongside.

Frequently asked questions