Sea and air freight run as separate operations, each with its own charges that have nothing to do with the freight rate itself. On the container side, the two that catch people out are demurrage and detention. They sound alike and are often billed together as demdet, but they are different things, and which one applies decides who is on the hook.
Demurrage vs detention
- Demurrage is the charge for a container that sits at the terminal too long — past the free time, before it is collected (import) or after it is delivered in but before it loads (export). It is about occupying the terminal's ground.
- Detention is the charge for keeping the carrier's container out of the terminal too long — you have taken the box to unstuff or stuff it and not returned it within the free days. It has nothing to do with the quay; it is the carrier's equipment being tied up.
Each carrier sets its own free time and its own daily rates, and they rise the longer the box stays. The combined bill, demurrage plus detention, is what people mean by demdet.
A customs inspection still costs you demurrage
A common misunderstanding: if customs pulls your container for a scan or a physical inspection and it sits for days, surely customs covers the demurrage? It does not. The inspection is a separate process; customs has no interest in the terminal clock and does not pay for it. The container is still occupying the terminal, so the demurrage runs and the cost falls to the cargo side, the client. Plan for it: a control can add days, and the demurrage runs the whole time.
Roll-over: whose bill is it?
When a carrier rolls your container — pushes it to a later sailing — the question is always why.
- Roll-over for the carrier's own reason (overbooked vessel, their operational choice): the carrier carries the demurrage.
- Roll-over because your paperwork wasn't right: the bill is yours. The usual causes are an export declaration (EX-A) that isn't in Portbase, or was never made, a missing or incomplete B/L instruction, or a dangerous-goods (IMO) declaration that is wrong, which also carries its own penalties. If the box rolls because a link in the documentation wasn't green, the demurrage that follows is for the booking party.
When the haulier misses the closing
If the truck is late for the closing (the cut-off to deliver the container to the terminal) because of traffic, that is the haulier's problem, not the carrier's — the carrier could do nothing about it. In shipping this kind of unavoidable event is called force majeure, or an "act of god". But "not the carrier's fault" does not mean "free": the forwarder ends up carrying those costs and has to pass them on to the client.
Why the choice of forwarder matters
A shipment moves without extra cost only when every link is green and runs smoothly: the carrier, the haulier, the terminal and customs all lined up. When one of them slips — and sometimes a system failure at the carrier, terminal or customs, common and itself force majeure, makes it slip — the cost lands on the forwarder's plate, and from there on the client. That is exactly why who you pick to book and move your shipment is not a detail. A forwarder who keeps every link green, and catches the paperwork before it rolls the box, is what keeps demdet off your invoice.
How Nexport Logistics handles it
We watch the free time, the closing and the documents on every shipment, so the box does not sit and the papers do not roll it. When demdet is unavoidable — a customs hold, an act of god — we are straight with you about why and what it costs, instead of a surprise on the invoice. Worried about demurrage on a lane? Email info@nexportlogistics.nl.
Related: Sea Freight · Container Shipping Lines · Bill Of Lading · Customs · Customs Scan Inspection