Carton Specification and Freight: How to Read the Numbers

A buyer plans a first shipment of cotton balls and zig-zag cotton, receives a price per carton, and books transport on the assumption that the goods will be heavy. The cartons are measured at the forwarder's warehouse and the volume is the constraint, not the weight. The rate that comes back is calculated on cubic metres, and the landed cost has to be rebuilt from the beginning.

The cause is the product itself. Absorbent cotton is a low-density material, and a carton of it is mostly air held in shape by film, board and the structure of the cotton. Weight and volume do not move together across the range, so a quotation that lists only a price per carton cannot be converted into a delivered cost per unit.

The specification to work from is the printed carton line: what goes into a bag, how many bags go into a box, how many boxes make a carton, and the external dimensions of that carton. Those numbers are enough to plan a container, a pallet and a stock room, and to see where the freight bill is going. This article explains how to read them, works two comparisons per cubic metre, and lists what to collect before freight is booked.

A light carton is limited by cube, not by weight

Transport is charged on chargeable weight, which is the greater of the actual weight of the shipment and a volumetric figure derived from its dimensions. Dense cargo, such as liquids or metal parts, is governed by actual weight. Absorbent cotton is governed by volume almost every time, because the product carries very little mass per unit of space.

The catalogue shows the shape of the problem. A carton of 10 g zig-zag packs holds 1 kg of cotton in 310 x 260 x 230 mm, or 0.0185 m³. A carton of 200 g zig-zag packs holds 12 kg in 480 x 300 x 490 mm, or 0.0706 m³. Divided through, the first carries roughly 54 kg per cubic metre and the second roughly 170 kg.

Neither figure is a fault in the packing. A small retail pack needs individual film bags, and the film, the air trapped between bags and the board of the carton all occupy space that carries no product. What the numbers show is that the smaller the pack, the larger the share of the freight bill that goes on moving packaging and air. A buyer comparing two suppliers on price per kilogram of cotton, without comparing the pack, is comparing two different transport propositions.

There is a practical consequence for range planning. Moving a line from a 10 g bag to a 25 g bag raises the mass carried per cubic metre from about 54 kg to about 77 kg, because the 25 g carton is 490 x 200 x 330 mm for 2.5 kg, but it cuts the number of retail bags in the same space. Pack size is a logistics decision as much as a merchandising one.

Reading a carton line correctly

A single line in the catalogue carries four facts in a fixed order, and reading them in the wrong order is the usual source of error. Take a cotton ball line described as 2.0 g, 500 balls per bag, 5 bags per carton, 530 x 380 x 420 mm. The count per bag comes first because it is the unit the end user handles, and bags per carton follows.

The 0.3 g cotton ball line is the only one in the range that passes through an inner box: 50 g bags, 12 bags to a box, 8 boxes to a carton, so 96 bags in a carton measuring 560 x 400 x 550 mm. That extra level points to a dispensing point where small units are handled often and a whole carton is too much to open at once.

Two sizes of the same product, measured per cubic metre

Take zig-zag cotton, where the same product is packed from 5 g to 1000 g. The 10 g carton measures 310 x 260 x 230 mm, or 0.0185 m³, and holds 100 bags of 10 g, which is 1 kg of cotton. One cubic metre therefore holds about 54 of those cartons, 5,400 retail bags and 54 kg of cotton.

The 200 g carton measures 480 x 300 x 490 mm, or 0.0706 m³, and holds 60 bags of 200 g, which is 12 kg. One cubic metre holds about 14 of those cartons, roughly 850 retail bags and 170 kg of cotton.

Set the two side by side and the trade-off is clear. The small pack delivers more than six times as many retail bags per cubic metre and about a third of the mass. For a pharmacy buying by the bag, the 10 g carton is the better shape to ship; for a hospital store room drawing on bulk, the 200 g carton moves three times as much cotton into the same slot.

The same arithmetic on cotton rolls is more striking. The 25 g carton is 370 x 230 x 370 mm, holds 200 rolls and carries 5 kg, so a cubic metre holds about 32 cartons, some 6,350 rolls and about 159 kg. The 4000 g carton is 910 x 310 x 450 mm, holds 6 rolls and carries 24 kg, so a cubic metre holds about 8 cartons, roughly 47 rolls and about 189 kg.

Roll count per cubic metre differs by more than a hundredfold, while mass per cubic metre differs by about a fifth. The 4000 g carton is the efficient way to move cotton between countries; the 25 g carton serves a clinic that opens one roll per dressing. A range needs both, and a freight plan that assumes one pack shape will misprice the other.

Why a 1000 g zig-zag carton is only 180 mm high

The height of a carton is set by how many layers of bags are stacked inside it, and by how those bags lie, not by how much the carton weighs. That is why the 1000 g zig-zag carton is the flattest item in the range at 180 mm, on a footprint of 580 x 510 mm.

Five bags of 1000 g are laid flat and side by side, forming a single layer. The carton height is then close to the thickness of one filled bag plus the board above and below it. Compare the 200 g line, where 60 bags go into a carton 490 mm high on a smaller footprint of 480 x 300 mm: there the bags are stacked in several layers, and the height accumulates.

At the other end, the 5 g carton measures 260 x 130 x 160 mm for 100 small bags. Despite weighing half a kilogram, it is the tallest item relative to its footprint in the family, because a hundred small bags build height quickly.

Three rules follow. Height is not a proxy for weight, so do not sort cartons by height when loading. A flat, heavy carton belongs at the bottom of a stack, where the floor carries its mass. And when a forwarder asks for stack height, answer in millimetres per carton with the number of layers you expect, because the flattest carton on the list is also the heaviest per layer.

Mixed pallets stack unevenly

Carton footprints in this range do not divide into one another. Cotton balls at 2 g to 5 g share 530 x 380 mm. The 1 g line is 550 x 380 mm, the 0.5 g and 10 g lines are 640 x 460 mm, the 5 g zig-zag is 260 x 130 mm and the 4000 g cotton roll is 910 x 310 mm.

Mixing a 640 x 460 footprint with a 530 x 380 one leaves a strip along one edge of every layer that no carton of the same family will fill. The layer either overhangs the pallet, which risks damage in transit, or the stack becomes stepped, which wastes height. Neither outcome shows up on a quotation.

The 910 x 310 mm cotton roll carton creates a different problem. It is long and narrow, so it spans across the smaller footprints underneath rather than resting on them, and a layer that bridges can crush the cartons below when the pallet is strapped.

Where a mixed pallet is unavoidable, three arrangements work better than random loading. Group cartons by footprint so each layer has one size. Put the smaller footprints on top. Photograph the agreed pattern and attach it to the order, so the warehouse that loads works from the plan that was priced.

What to collect before you book freight

Five figures decide the quotation, and four are usually missing from a first enquiry. Carton count comes first: how many cartons the order makes, split by pack size, because a mixed order produces a mixed pallet.

Net and gross weight come next, and both must be measured. Net weight is the product inside the bags. Gross weight adds the film, any inner box, the carton board and the labelling, which on a light product can be a meaningful share of the total. A gross weight guessed from the net figure will misstate chargeable weight.

Pallet pattern is the fourth: cartons per layer, layers per pallet, and whether the pallet ships as a unit or the cartons load loose. HS code readiness is the fifth and belongs to the importer. The invoice description has to match what is inside the carton, including whether the goods are sterile.

A short specification sheet prevents most quotation errors. It should carry the pack size or sizes, the carton count, the measured gross weight per carton, the dimensions, whether the consignment ships palletised or loose, the destination and the terms of sale. With those in hand a forwarder can quote on the same basis as another forwarder, and two quotations become comparable rather than merely different.

What to confirm before ordering

• Carton dimensions to the millimetre for each pack size, not one figure for the whole family
• Count per bag, bags per box and boxes per carton confirmed in writing
• Net weight and gross weight per carton, taken from a weighed carton
• Carton count for the order, split by pack size
• Pallet pattern, layers per pallet and maximum stack height
• Whether cartons are to be marked with a customer pack or kit code
• HS code and product description agreed with your customs broker
• Country of origin marking as required at destination
• Whether a certificate of analysis travels with the shipment
• Which documents the forwarder needs before the booking closes

Can freight cost be calculated from carton dimensions alone?

No. Dimensions give volume, and volume is only half of chargeable weight. You also need gross weight per carton, the carton count, the route and the terms of sale, because the volumetric rule applied is the carrier's own. The catalogue supplies dimensions and pack counts; the figure to add is a weighed gross weight per carton, which depends on film gauge and board grade.

Why does a heavier carton sometimes take less pallet height?

Because height follows the number of bag layers, while mass follows the fill weight. The 1000 g zig-zag carton carries 5 kg in a single layer of five flat bags and stands 180 mm high, while the 5 g carton carries 0.5 kg in 100 small bags and stands 160 mm high on a much smaller footprint. Loading by height puts a heavy carton where a light one was planned.

Do the catalogue dimensions include the pallet?

No. They are external dimensions for the closed carton. Palletised dimensions are larger, depend on the pattern you agree, and are the figures a forwarder will normally want for a full container load. Ask for both, and state which one your rate is based on.

The complete set of carton dimensions, pack counts and volumes for cotton balls, zig-zag cotton and cotton rolls is printed in the 2025 catalogue, which can be read alongside the individual product pages for each pack size. Buyers planning a first container often find it quicker to send the destination, the pack sizes under consideration and the annual volume, and ask for the carton and pallet schedule that matches. The cotton ball, zig-zag cotton and cotton roll ranges are listed by pack, and the quality documentation that travels with a shipment is described on the quality page.