What carton data decides your freight bill

Unit price is the number everyone negotiates. The carton is the number that decides what it costs to move the goods, and on light bulky products the carton can matter more than the price.

Most suppliers do not volunteer carton data. The ones who publish it have made their product quotable, and that is worth noticing on its own.

You are charged for space, not weight

Less than container load sea freight is normally charged on whichever is greater, the volume in cubic metres or the weight in tonnes. Air freight and courier services apply a volumetric weight calculated from the outer dimensions, and charge on whichever is greater.

For most consumer and assistive goods, volume wins. You are buying space on a vessel or an aircraft, and how efficiently your product fills that space is decided at the factory when they choose the carton.

The three numbers you need for every item

1. Pieces per carton.
2. Outer carton dimensions, length by width by height.
3. Gross weight per carton.

From those three you can calculate cubic metres per carton, cubic metres per piece, and freight cost per piece. That last figure is what makes two quotes comparable. Unit price alone does not.

The arithmetic

A carton measuring 60 by 40 by 40 centimetres is 0.096 cubic metres.

At twenty pieces per carton, that is 0.0048 cubic metres per piece.

At ten pieces per carton, the same carton is 0.0096 cubic metres per piece. The freight cost per piece has doubled and nothing about the product has changed.

This is why pieces per carton is a term to negotiate rather than a fact to accept. Ask whether the product can be packed more densely, whether it nests, and whether it can ship knocked down and be assembled on arrival.

Where it goes wrong

• Inner cartons quoted as outer cartons. Ask explicitly for the outer carton, the one that actually gets loaded.
• Assembled when it did not need to be. A frame shipped assembled can occupy several times the volume of the same frame flat packed.
• Nesting not used. Bowls, chairs and basins that nest can halve their volume. Many suppliers pack them as though they do not.
• Carton dimensions that stow badly. Odd sizes leave dead space around them. A slightly smaller carton that fits the pallet footprint can ship more units per cubic metre than a larger one.
• Rounding. Carriers round dimensions up. Half a centimetre over a round number can cost a whole one.

The costs that follow carton count

Carton count, not order value, drives several other line items. Labelling is per carton. Inspection sampling is drawn per carton. Palletising, and the shrink wrap and dunnage that go with it, are per carton. Warehouse receiving at the other end is frequently charged per carton too.

Two quotes at the same unit price and the same total volume can differ meaningfully once the one with three times as many cartons has been handled at both ends.

What to put in the request for quotation

Ask for this with the price, not after you have chosen a supplier. A supplier who cannot produce it quickly is telling you something about how often they export.

• Model number and a photograph of the product in its carton
• Pieces per inner carton and pieces per outer carton
• Outer carton dimensions in centimetres
• Net and gross weight per outer carton
• Whether the item nests or ships knocked down, and the carton data for that option
• Carton material and whether it is suitable for sea freight

Questions to ask

1. What are the outer carton dimensions and pieces per carton for each item?
2. Can this be packed more densely, and what would that cost?
3. Does it nest or ship knocked down?
4. What is the cubic metre figure for the full order as quoted?
5. How many cartons will the order be?

The short version

Get pieces per carton, outer carton dimensions and gross weight for every item before you compare prices. Convert them to cubic metres per piece. Then compare landed cost per piece, which is the only number that decides anything.

Verified September 2026. Next review March 2027. Freight is charged under carrier tariffs that differ by lane, mode and carrier. Use these methods to compare quotes, and confirm the rating basis with your forwarder before you rely on a figure.