Every Millimetre of Carton Is Paid for at the Port

Two Numbers Price Every Shipment

Sea freight is priced on cubic metres or on a container. Air freight is priced on chargeable weight, which is the greater of the actual weight and the volumetric weight: length times width times height in centimetres, divided by 6,000 for most carriers. Both numbers come from the carton, and neither comes from the product.

That is the whole argument. A buyer negotiates the unit price for a week and accepts the carton the factory already uses, which is often a carton designed for domestic delivery: slightly too large, single wall, no corner protection, palletised on whatever was in the yard.

The gap between a domestic carton and an export carton is a few percent of the goods value. The gap between a well-designed export carton and a careless one is often ten percent of the freight, and on light bulky goods the freight is the larger number.

Millimetres Become Cubic Metres

A carton of 60 by 40 by 40 centimetres is 96 litres, or 0.096 cubic metres. Reduce the height by five centimetres and it becomes 84 litres, a reduction of 12.5 percent. On a thousand cartons that is twelve cubic metres, which on a Europe lane is a fifth of a container.

Five centimetres is usually available. Cartons are frequently sized to a round number, or inherited from a previous product, or built with an air gap because the factory's existing die was the right price. The factory will not volunteer the change and will not resist it either, if the buyer asks before the order is placed rather than after the goods are packed.

Two rules of thumb help at the quotation stage. First, ask for the carton dimension and the cubic metres per carton on the quotation itself, not as a follow-up email; a supplier who cannot fill that field has not shipped export before. Second, compare quotations on cubic metres per unit of product, not on carton price, because a cheaper carton that is two centimetres deeper costs more in freight than it saves in board.

There is a floor. Cartons have to protect the goods and carry a legible mark, and shaving volume until the product is damaged is a false economy that shows up as a claim rather than as a saving.

Board Grade Is a Structural Decision

Corrugated board is specified by flute and by edge crush, the latter quoted as ECT in kilonewtons per metre or in the older pounds per inch figure.

• Single wall, B flute. Around 3 mm. Fine for light goods in shallow stacks, and what most domestic cartons are.
• Single wall, C flute. Around 4 mm. The general export default for consumer goods.
• Double wall, BC flute. Around 7 mm. For heavy goods, tall stacks, or long sea voyages where humidity softens the board.
• ECT 32 and above. A common export specification for stacking strength. Below ECT 26 a tall stack in a humid container is a gamble.

Humidity is the part buyers underestimate. Board loses a large share of its compression strength at high relative humidity, and a container crossing the tropics sits at high humidity for weeks. A carton that stacks three high in a Guangdong warehouse in April may not stack two high in a Rotterdam warehouse in June, because it arrived soft.

Ask for the board grade in numbers, and for the stacking height the factory has tested. If the answer is "strong", the specification is whatever the carton plant had that week.

The Pallet Decides the Load Plan

Palletising is the single largest source of wasted space in export shipping, and it is invisible on a quotation.

A standard pallet is 1200 by 1000 millimetres in much of the world, 1200 by 800 in Europe, and 1219 by 1016 in North America. A 40ft container floor is about 12.03 metres by 2.35 metres. Load 1200 by 1000 pallets two abreast and you use 2.0 metres of the 2.35 available, leaving 35 centimetres of unusable width down one side, and the length divides into ten pallets with a gap at the door.

• Pallet height. A 15 centimetre pallet under a 1.2 metre stack costs a container a full layer of cargo over a hundred pallets.
• Overhang. Cartons that overhang the pallet edge are crushed by the pallet next to them, and the overhang itself is not protected by anything.
• Double stacking. Two pallets high only works if the lower cartons were designed for it. Usually they were not.
• Floor loading. Cartons loaded loose, stacked to the roof, use the container completely and need a loading plan and a labour team. For dense goods this is often the right answer.

The comparison to run is simple: palletised cubic metres used against loose-loaded cubic metres used, for the same goods. On light bulky cargo the difference is routinely between five and fifteen percent of the container.

Inner Packing Protects the Margin

Outer cartons protect the goods from the journey; inner packing protects them from each other.

The options, roughly in order of cost: moulded pulp, corrugated inserts, foam, air-filled columns, and a bag. Each has a place, and the choice is usually made by the factory on the basis of what it already owns rather than what the product needs.

• Moulded pulp. The best protection per unit of volume for fragile and shaped goods, and recyclable in most markets, which increasingly matters to retail buyers.
• Corrugated inserts. Cheap, effective for boxy products, and they fold flat for storage.
• Foam. Effective and bulky. It protects the product and pays freight on its own volume.
• Air columns. Good protection for bottles and glass, and they deflate if punctured, which is exactly when protection is needed.
• The bag. Not packing. A bag around a product in a carton is a bag.

Ask for the drop test result rather than the packing description. A factory that has drop tested can give a height and an outcome; one that has not will describe the packing as strong.

Marks Are Read by Machines and People

Carton marks are not decoration. They are the interface between the factory, the warehouse, the customs officer and the receiver, and each reads a different part of them.

• Shipping marks. Consignee, reference, destination port, carton number and total. This is what a customs officer uses to match a carton to a declaration.
• Handling symbols. This way up, fragile, keep dry, stacking limit. In pictogram form, because the warehouse may not read English.
• Weight and dimensions. Gross weight and carton size, printed. This is what a carrier uses to plan a load and what a worker uses to decide whether to lift it alone.
• Origin. Country of origin marking where the destination requires it, which is a legal statement and not a design element.
• Side marks on pallets. A pallet of forty cartons needs a pallet label, or the receiver counts forty times.

Hand-written marks in marker pen are the clearest signal that the packing was organised at the last minute. They also fade, smudge and get rained on, which is how a carton arrives at destination with no identity.

What to Write in the Purchase Order

Packaging specified verbally is packaging that changes. Eight lines in a purchase order fix it.

• Carton dimensions, external, in millimetres, and cubic metres per carton.
• Board grade: flute, wall construction and ECT figure.
• Units per carton, and cartons per pallet or per layer.
• Inner packing type and material.
• Pallet type, dimensions and treatment: heat treated, ISPM 15 stamped, or no pallet.
• Mark content, position and print method.
• Drop test requirement and the height.
• Whether the buyer or the supplier pays for the packaging, and whether the carton is charged separately on the invoice.

That last line matters more than it looks. When packaging is charged separately it appears on the commercial invoice as a value, which changes the customs valuation of the shipment. When it is included in the unit price it does not. Either is acceptable; both being true at once is a question at the destination port.

Checking Packaging at the Fair

Packaging is the cheapest thing to check at a booth and the thing buyers check least, because the sample is on a shelf and the carton is in the back.

Ask to see the export carton. Not the retail box; the master carton, sealed, with its marks. Then do four things.

• Measure it. Tape measure, three dimensions, written down.
• Read the board grade print, which is usually stamped on the bottom flap with the maker and the ECT figure.
• Lift it, if it is full. Weight in the hand is the only reliable guide to whether the carton matches the claim.
• Look at the corners. Crushed or split corners on a sample carton mean the plant is producing them that way.

Then ask the question that separates a factory from an assembler: how many cubic metres does one carton occupy, and how many cartons fit in a 40ft high cube. A factory that ships regularly answers in seconds. One that quotes containers from a forwarder will estimate, and the estimate will be optimistic.

Pallet dimensions, board grades and container internals above are standard figures. The load plan for an actual order has to be calculated from the carton schedule of that order.

FAQ