Sea vs Air Freight: Which to Use and When (FCL vs LCL)
Every shipment forces the same question: fly it or float it. Air freight gets your goods there in days but costs a multiple of sea; sea freight is cheap per unit but takes weeks and ties your cash up longer. The right answer is not always the same one, and it usually comes down to three numbers: how much volume you are moving, how much each unit is worth, and how soon you need it. This guide walks through the tradeoffs and the shipping terms that decide your bill.
The core tradeoff
- Speed: air freight typically lands in a few days to a week; sea freight runs several weeks door to door, sometimes longer with port congestion.
- Cost: air is priced high and by weight, so it punishes heavy or bulky goods; sea is far cheaper per unit for anything with real volume.
- Cash flow: a faster shipment means your money is tied up for less time, which for some businesses is worth paying for.
- Carbon and handling: air has a much higher footprint per unit; sea involves more handling steps and a longer paper trail.
When air actually makes sense
Air is not just the panic option. It is the right call when the goods are small and light relative to their value, when you are shipping samples or a first small batch, when you are restocking a bestseller that is about to sell out, or when a delay would cost you more than the freight premium. For a pallet of high-margin electronics that you can sell the day they land, air can be the cheaper choice once you account for lost sales.
How air freight is priced: chargeable weight
Airlines charge on chargeable weight, which is the greater of the actual weight and the volumetric weight. Volumetric weight converts the size of your shipment into a weight figure, so a big box of light goods is billed as if it were heavier. This is exactly why bulky, low-value products almost never make sense by air: you pay for the space they take up, not just what they weigh.
FCL vs LCL: the two ways to ship by sea
If you go by sea, you are choosing between a full container and a shared one.
- FCL (Full Container Load): you book a whole container, usually a 20-foot or 40-foot. You pay a flat rate for the box whether it is full or not, so the more you fill it the cheaper each unit becomes.
- LCL (Less than Container Load): your goods share a container with other shippers, and you pay for the space you use, priced per cubic metre. Great for small orders, but with more handling and a slightly higher risk of delay.
The volume break-even
The decision between LCL and a full container comes down to CBM, or cubic metres. As a rough rule of thumb, LCL is the cheaper option up to somewhere around 13 to 15 CBM. Past that, a 20-foot container usually works out cheaper per unit even if you do not completely fill it, because LCL pricing scales with every cubic metre while a container is a fixed price. Knowing your CBM is the only way to make this call properly.
A 20-foot container holds roughly 28 to 33 CBM of usable space and a 40-foot around 58 to 66 CBM, but you rarely pack to the ceiling. Work from your real CBM, not the container's maximum.
Not sure how much space your order takes or whether it fits a container? Our free CBM and container calculator works out your volume and how it loads. Open the free CBM calculator
Do not forget the ex-factory date
Whichever mode you pick, transit time is only half the timeline. The other half is when the goods actually leave the factory. Air freight cannot rescue an order whose ex-factory date has already slipped two weeks; you will just pay a premium to partly catch up. Plan the freight mode around a realistic ex-factory date, not a hopeful one.
Common mistakes
- Choosing air on price panic when the ex-factory date, not transit, is the real reason you are late.
- Shipping bulky, low-value goods by air and getting hit by volumetric weight.
- Sticking with LCL past the point where a full container would be cheaper.
- Comparing only the freight quote and ignoring the cash tied up by the longer sea transit.
The bottom line
Ship by sea when you have volume and time, and by air when the goods are small, valuable or urgent enough to justify the premium. Use your CBM to decide between LCL and a full container, and always plan the mode around a realistic ex-factory date. Freight is a lever, not a rescue.
Related guides
- LCL vs FCL: When to Ship Less Than a Full Container
- How to Calculate CBM and Choose the Right Container
- Ex-Works, FOB, CIF: Incoterms Explained for Importers
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