Most importers know the word demurrage. Fewer can say precisely where it stops and detention begins, and fewer still track chassis per diem at all.
Most importers know the word demurrage. Fewer can say precisely where it stops and detention begins, and fewer still track chassis per diem at all. That vagueness is expensive, because the three charges have different owners, different triggers and different fixes.
Demurrage: the container is still at the terminal
Demurrage accrues when a loaded import container sits inside the terminal past its free time. It is charged by the ocean carrier or the terminal, and the clock runs on their calendar, not yours. Customs holds, agency exams and appointment scarcity all extend it, and none of them pause it.
Detention: the container has left and not come back
Once the box is out of the gate, detention takes over — the charge for keeping the ocean carrier’s equipment beyond the allowed days. This one is largely within your control, because it is driven by how fast you unload and how fast the empty gets returned. It is also the charge most often blamed on the carrier when the real delay was at the receiver’s dock.
Per diem: the chassis is metered separately
The chassis under the container is usually leased and billed by the day, independent of both clocks above. It is easy to miss because it appears as a separate line rather than a penalty. A container sitting at a warehouse for three extra days is accruing detention on the box and per diem on the chassis at the same time.
Where the money actually leaks
Almost never on the drayage move itself. It leaks in the gaps: waiting on a customs release before dispatch, a receiver who cannot take the delivery until Thursday, an empty that sits on the yard because nobody scheduled the return. Every one of those is a scheduling problem wearing a fee’s clothing.
What a carrier can and cannot do
A carrier can watch your free time and prioritise accordingly, move the moment a hold clears, and schedule the empty return rather than waiting to be asked. A carrier cannot make your receiver take the load early, and cannot pause a clock the ocean carrier controls. Be suspicious of anyone who implies otherwise.
The question worth asking
When you get an invoice with one of these charges on it, ask which clock it was and where the days went. A carrier who can answer that specifically is tracking your freight. A carrier who cannot is passing through a bill they never looked at.