The usual shorthand — sea is cheap and slow, air is fast and expensive — is right often enough to be dangerous. For a surprising number of shipments out of Vietnam the two are much closer than the rate sheet suggests.
Start with chargeable weight, not gross weight
Air freight is priced on the greater of actual gross weight and volumetric weight, where volumetric weight is length × width × height in centimetres divided by 6,000. A pallet of garments that weighs 180 kg can easily be charged as 420 kg. A carton of electronic components at the same volume may be charged on its real weight. That single calculation moves the comparison more than any negotiation will.
Then count the full door-to-door clock
Port-to-port is not the number that matters. A realistic sea shipment from Ho Chi Minh City to Northern Europe is 5–7 days of pre-carriage and export formalities, 22–28 days on the water, then 3–5 days for import clearance and delivery. Air is 1 day out, 3–5 days in transit, 1–2 days in, and it does not wait for a weekly sailing.
Add the costs that never appear on the quotation
- Working capital. Stock on the water is cash you cannot use. Five extra weeks on a US$150,000 shipment is real money at any financing rate.
- Safety stock. Longer, more variable lead times force you to hold more inventory to keep the same service level.
- Obsolescence and season. Fashion, electronics and anything with a promotional date lose value while they sail.
- Failure cost. A production line stopped for want of a component is rarely cheaper than an air waybill.
The practical rule
Dense, high-value, time-sensitive or small consignments frequently justify air. Bulky, low-value, forecastable goods almost never do. Anything in between deserves an actual calculation rather than an assumption.
Send us a packing list and we will quote both modes side by side, with the chargeable weight shown so you can check the arithmetic yourself.