The box you ship in constrains what you can ship, what it costs and how long it takes. Choosing it late is expensive.
Freight is usually the second largest line in a landed cost and the one most often estimated rather than calculated. Most of the estimate error comes from choosing the wrong mode or the wrong box.
| Type | Carries | Watch for |
|---|---|---|
| 20ft dry | Dense cargo that weighs out before it cubes out | Weight limits bind before volume does |
| 40ft dry | Bulky cargo that cubes out first | Nearly the same cost as a 20ft on many lanes |
| 40ft high cube | Extra height for volume cargo | Not accepted at every inland facility |
| Reefer | Temperature-controlled goods | Power at every leg, including the yard |
| Flat rack | Oversized machinery | Lashing and out-of-gauge surcharges |
| Open top | Cargo loaded by crane from above | Tarpaulin and weather exposure |
| Tank | Bulk liquids and chemicals | Cleaning certificates between cargoes |
A full container is priced per box. A part load is priced per cubic metre or tonne, whichever is greater, plus a fixed handling charge at both ends. There is a crossover point — usually somewhere around a third to a half of a container — beyond which buying the whole box is cheaper than paying for the space you use. Below it, LCL wins; above it, people routinely overpay by not checking.
When freight is a small share of product value, speed is cheap.
Perishables where sea transit consumes the sellable window.
When a production line stopping costs more than the freight premium.
First consignments, where time to market outweighs unit economics.
The port pair and lane on a shipment record tells you which of these decisions a competitor made, and usually why.
Somewhere between a third and a half of a container, buying the whole box becomes cheaper than paying per cubic metre. A surprising amount of LCL freight is bought past that point.
Every container has two limits — a payload weight and an internal volume — and a cargo hits one of them first. Dense goods weigh out: the box is legally full long before it looks full, and you pay for space you cannot use. Light goods cube out: the box is physically full at a fraction of the permitted weight. Knowing which applies to your cargo decides whether a 20ft or a 40ft is the economic choice, and it is a calculation most people do once and then rely on forever.
The counter-intuitive result is that a 40ft container often costs only modestly more than a 20ft on the same lane, because the cost drivers are slot and handling rather than volume. For cargo that cubes out, the 40ft is almost always cheaper per unit. For cargo that weighs out, the 20ft is frequently the right answer and the 40ft simply moves air at a premium.
| Cargo type | Limit hit first | Usually right box |
|---|---|---|
| Metals, stone, liquids in drums | Weight | 20ft dry |
| Packaged consumer goods | Volume | 40ft or 40ft high cube |
| Garments and textiles | Volume | 40ft high cube |
| Machinery and parts | Weight, usually | 20ft, or flat rack if out of gauge |
| Perishables | Volume, plus temperature | 40ft reefer |
| Bulk liquids and chemicals | Weight | Tank container |
Below the full-container threshold, cargo moves as part loads and is charged on the greater of weight and measurement, plus fixed handling at both ends. Those fixed charges are what make small part loads expensive per unit, and they are also what create the crossover: past roughly a third to a half of a container, the fixed costs and the per-cubic-metre rate together exceed what the whole box would have cost. A surprising volume of freight is bought past that point because nobody rechecked it after order sizes grew.
Ocean and air are not the only options. Rail corridors, road-ferry combinations and sea-air hybrids exist on specific lanes and occupy the middle ground on cost and time that is otherwise empty. They are less visible because they are lane-specific rather than universal, which means the only way to find out whether one serves your route is to ask a forwarder who works that corridor. The shipment record helps here too: the modes competitors actually use are visible in the data.
Mode and box decisions are usually made once, at the first shipment, and then inherited indefinitely. Order sizes grow, lanes change, and the original decision quietly stops being the right one.
Everything above is a framework, and a framework is only worth what it survives contact with. The useful discipline is to test each assumption against what consignments actually did, because customs data is one of the few commercial sources where the underlying event — goods crossing a border — physically happened and was documented under legal obligation at the time.
Fix the tariff line before anything else. Every filter, every duty figure and every comparison downstream depends on it.
Learn more ›A single period is a snapshot. Three years separate a trend from seasonality, and let you discount the incomplete recent periods.
Learn more ›Frequency and consistency beat size. A steady mid-scale counterparty is usually a better prospect than an occasional large one.
Learn more ›Declared unit values tell you the range you are entering before you quote into it.
Learn more ›Two failure modes account for most wrong conclusions drawn from trade data, and both are easy to avoid once named. The first is reading the incomplete tail of a series as a decline — authorities publish on a lag and revise afterwards, so the last one or two periods will fill in after you look. The second is reading a value movement as a demand movement, when declared value can move because volume moved, because unit price moved, or because the product mix inside a tariff line changed.
Customs data covers goods that crossed a border. It does not cover services, domestic trade, margin, contract terms or intent. Treat it as a dated, quantified observation to corroborate — not as a conclusion that arrives finished.
The difference between teams that get value out of trade data and teams that ran one interesting project is almost never analytical sophistication. It is whether the work became a routine. A saved query reviewed weekly, a short written note against each counterparty you assessed, and a standing habit of checking the period stamp before quoting a figure will out-perform an elaborate one-off study within a quarter, because markets move and a study does not.
The second habit worth building is writing down not just what you concluded but why and when. Records get revised, prices move, and counterparties change behaviour. Six months later nobody remembers whether a supplier was rejected on volume, on price band or on timing, and without that note the assessment simply gets repeated from scratch. A one-line rationale is what converts a list into institutional knowledge, and it costs seconds at the point where the thinking has already been done.
Finally, be explicit with colleagues about the confidence attached to any figure you circulate. A declared value from a complete period, controlled for origin and unit, is strong evidence. The same figure pulled from an incomplete recent period, averaged across a whole chapter, is barely evidence at all — and the two look identical once they are in a slide. Saying which one you have is what keeps trade data credible inside an organisation over time.
A full container load is priced per box regardless of how full it is. A less-than-container load is priced on the greater of weight and volume plus fixed handling at both ends, which is why small consignments cost disproportionately more per unit.
Almost always, per unit, for cargo that cubes out rather than weighs out. The lane cost difference between the two boxes is usually much smaller than the capacity difference.
A 40ft container with roughly a foot of extra internal height. Useful for volume cargo, but not accepted at every inland facility, so check the whole route before committing.
The shipment record shows the port pair and, by implication, the mode. Air movements appear on air waybills rather than ocean manifests, and the routing itself usually makes the mode obvious.
Markets refresh on their customs authority's own release cycle — monthly for most, 45 to 60 days for a few. The most recent one or two periods are always still filling in, so exclude them when you are reading a trend rather than treating the gap as a decline.
Yes. Give us the HS code or a product description and the market you care about, and we will return a sample of live customs records filed against it.
Keep reading
The next questions this one usually raises are covered in Air freight or sea freight, Reading port data for logistics decisions and Cold chain and perishable exports. Each picks up where this article stops, and together they cover the sequence a consignment actually goes through — classification and duty before anything moves, documentation and payment while it moves, and verification of the counterparty before any of it is committed to. Reading them in that order is usually more useful than reading them by topic.
The decision is not about speed, it is about what speed is worth against what it costs for your particular cargo.
Learn more ›The port pair on a record is the closest thing to a free freight quotation, and it settles arguments that otherwise run on assertion.
Learn more ›Perishables fail in the gaps between legs, not in the middle of them.
Learn more ›