What is demurrage?

On an import, the container is discharged from the ship and placed in the terminal’s stack. From then a set number of free days runs — the free time. If the box is still in the terminal when those days end, demurrage is charged for every further day until a truck takes it out through the gate. That gate-out stops demurrage and at the same moment starts the clock on the other charge, detention, which runs until the box is returned empty.

On an export it works in mirror image: a full container delivered to the terminal too early, or left there because it missed its ship, can run through its free days before loading. How many days are free, the daily rate, whether weekends and holidays count and how the rate steps up are set by the shipping line’s tariff and by the terminal, and they differ by port and by contract. They can be negotiated before booking and rarely after.

The charge normally comes from the shipping line, on an invoice that has to be paid before the container is released; the terminal may bill its own storage separately. It falls on whoever the contract of carriage and the sale terms make responsible for the cargo at that port — at destination, usually the importer. Some lines quote one combined allowance and bill both charges together as “demurrage and detention” (D&D), and in the United States the daily charge on equipment is often called per diem, so read which clock a quoted “free time” covers.

The date to find is the last free day. It is on the line’s arrival notice and in the line’s or the terminal’s online system, and it is counted from the discharge event. We do not show where a container is: our container tracking page checks the number and sends you to the line’s own tracker, where discharge and gate-out are published.

The usual mistake is to assume the clock waits while something outside your control is sorted out. As a rule it does not: a customs inspection, a missing document, an unpaid freight invoice or a haulier with no free slot all leave the container in the stack with free time running. The cost of a late bill of lading is counted in days of demurrage, and those days tend to cost more the longer they run.

The second mistake is using the two words as one. An importer who believes “demurrage” covers everything collects the box on the last free day, keeps it at the warehouse for a week, and is billed detention for it. They are two clocks with two allowances unless the line states that it has merged them. Clear the documents before arrival, book the truck against the last free day, and ask for more free time when you book, not when the invoice arrives.