- Sea freight is usually the cheapest per unit for larger volumes; air and courier buy speed at a much higher price.
- As a rule of thumb, once a sea shipment reaches roughly 13–15 CBM, a full container often costs about the same as or less than shared LCL space.
- Carriers charge by chargeable weight: the greater of actual weight and volumetric weight.
- Always confirm container capacity, weight limits and transit times with your forwarder for the specific route.
The freight mode you choose affects your landed cost, your cash flow, how much stock you need to hold and how quickly you can react to demand. There is no single best mode. The right choice depends on the size and weight of the shipment, the value of the goods, how urgently you need them and the route. This guide compares the main options and explains the calculations forwarders use to price them.
The main freight modes at a glance
| Mode | Relative speed | Relative cost | Best for | Typical minimum |
|---|---|---|---|---|
| Sea FCL (full container) | Slowest | Lowest per unit at volume | Large, regular orders; heavy or bulky goods | One container, used exclusively by you |
| Sea LCL (shared container) | Slow, plus consolidation time | Low to moderate per unit | Smaller orders that do not fill a container | Often around 1 CBM minimum charge |
| Air freight | Fast | High | Urgent, high-value or lightweight goods | Minimum charge per shipment, varies by carrier |
| Express courier | Fastest door to door | Highest per kg | Samples, documents, small parcels | No real minimum |
| Rail (on certain routes) | Between sea and air | Between sea and air | Mid-value goods on rail-connected corridors | Usually container or groupage space |
These are general patterns, not guarantees. Rates move with demand, fuel prices and capacity, and on some routes the gap between modes narrows or widens sharply.
FCL vs LCL: where the breakeven sits
With FCL (full container load) you pay for an entire container whether you fill it or not. With LCL (less than container load) you pay for the space your cargo occupies, and a consolidator shares the container with other shippers. LCL looks cheaper for small volumes, but it carries extra handling charges at both ends, takes longer because cargo must be consolidated and deconsolidated, and involves more handling, which raises the risk of damage.
A widely used rule of thumb is that once your shipment reaches roughly 13 to 15 CBM, a 20-foot container often costs about the same as LCL, or less. Above that, FCL is usually the better choice, and you gain speed, security and simpler handling. The real breakeven depends on the route and current rates, so ask your forwarder to quote both. Use the CBM calculator to work out your volume from carton dimensions.
Chargeable weight: how carriers bill you
Carriers want to be paid for the space light, bulky cargo occupies as well as for heavy cargo. So they compare actual weight with a volumetric (dimensional) weight and charge whichever is greater.
- Air freight: volumetric weight in kg = length × width × height in cm ÷ 6,000. That is a ratio of 1 CBM to about 167 kg.
- Express courier: most couriers use a divisor of 5,000, equal to 1 CBM to 200 kg. Some use other divisors, so check.
- Sea LCL: charged per “weight or measure” (W/M), where 1 CBM is treated as equal to 1,000 kg. You pay on whichever figure is higher.
Example (illustrative): a carton measures 60 × 40 × 40 cm and weighs 8 kg. Its air volumetric weight is 96,000 ÷ 6,000 = 16 kg, so you pay for 16 kg, not 8. By courier it is 96,000 ÷ 5,000 = 19.2 kg. The volumetric weight calculator handles these sums for whole shipments.
Reducing empty space in cartons, using flat-pack designs or switching to a slightly smaller box can lower chargeable weight more than any rate negotiation. Ask your supplier for carton dimensions before you finalise packaging.
Container sizes
| Container | Approx. internal volume | Approx. max payload | Practical loadable volume |
|---|---|---|---|
| 20′ standard (20GP) | ~33 CBM | ~25–28 tonnes | ~25–28 CBM |
| 40′ standard (40GP) | ~67 CBM | ~26–27 tonnes | ~55–60 CBM |
| 40′ high cube (40HC) | ~76 CBM | ~26–27 tonnes | ~65–70 CBM |
These figures are approximations. Exact dimensions and payloads vary by container owner and build, and road weight limits in the origin or destination country may allow far less than the container’s rated payload. Always verify with your carrier or forwarder. Cartons and pallets never fill every cubic centimetre, which is why practical capacity is lower than internal volume. Plan your load with the container load calculator and the pallet calculator.
What affects transit time
The time on the water or in the air is only part of the journey. Door-to-door time also includes:
- Pickup and inland transport to the port or airport.
- Cut-off times for cargo and documents, and the sailing or flight schedule.
- Transhipment at intermediate hubs, which adds days and risk of delay.
- Port or airport congestion, weather and seasonal peaks, such as the period before major holidays.
- Consolidation and deconsolidation time for LCL and groupage cargo.
- Customs clearance and any inspections at both ends.
- Final delivery and appointment availability at your warehouse.
Ask for door-to-door estimates rather than port-to-port, and build a buffer into your stock planning.
Freight forwarder, carrier or NVOCC?
- Carrier: the company that actually operates the ship, aircraft, train or truck. Small shippers rarely book directly with ocean carriers or airlines.
- Freight forwarder: organises the shipment on your behalf. It books space with carriers, arranges pickup and delivery, prepares documents and often handles customs clearance through an in-house or partner broker. For most small businesses, a forwarder is the main point of contact.
- NVOCC (non-vessel operating common carrier): buys space from ocean carriers and resells it, issuing its own house bill of lading. Many forwarders act as NVOCCs. Consolidators offering LCL services usually operate this way.
Choose a forwarder with experience on your trade lane and product type, transparent all-in quotes and responsive communication. Your Incoterm decides whether you or your supplier books the main freight; see Incoterms 2020 explained. To compare options, request a freight quote.
Freight quotes often differ in what they include: origin charges, destination charges, customs clearance, insurance and delivery. Ask every forwarder for a breakdown on the same basis before you choose the cheapest headline rate.
Frequently asked questions
When should I choose air freight over sea?
Air is worth considering when goods are urgent, high in value relative to their weight, perishable or needed to fill a stock gap. For heavy, bulky or low-margin goods, the cost of air usually outweighs the benefit.
Is LCL slower than FCL?
Usually, yes. LCL cargo has to be consolidated at origin and separated at destination, and it may wait for enough cargo to fill a container. That can add several days at each end compared with a full container on the same route.
What does CBM mean?
CBM stands for cubic metre. It is calculated by multiplying length, width and height in metres. Forwarders use it to price sea freight and to plan container loading.
Can I mix products from different suppliers in one container?
Yes. Many forwarders and sourcing agents offer consolidation, collecting goods from several suppliers into one shipment. This can give you FCL economics without a single large order from one factory.
Is rail freight available for my route?
Rail is practical only on connected corridors, such as certain routes between Asia and Europe. Ask a forwarder whether rail services operate on your lane and how their price and transit time compare with sea and air.
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This guide is general education, not legal, tax or customs advice. Rules change and vary by country — confirm details with your customs authority or a licensed broker before you ship. Spotted something out of date? Tell us.