Demurrage and Detention: How to Avoid Extra Container Charges

Demurrage and detention are two of the most common — and most avoidable — extra charges in container shipping: demurrage is for a full container sitting at the port too long, detention is for keeping the container too long after you take it away. They catch importers out because they accrue quietly, per day, and can add up fast. Here is what they are and how to keep them off your invoice.

Key takeaways

Demurrage = your full container sits inside the port/terminal past the free time, waiting to be picked up.
Detention = you hold the container outside the terminal past the free time before returning the empty.
Carriers grant a few free days on each side; beyond that, charges accrue per container, per day on a rising scale.
The usual triggers are customs delays, slow unloading, empty-return problems and documentation issues.
Both are almost always preventable: clear customs early, plan unloading, know your free days and return empties promptly.

Two charges, often confused

They sound similar and are frequently lumped together, but they cover different things:

Demurrage is charged when your full container sits at the port/terminal beyond the allowed free time, waiting to be picked up.
Detention is charged when you keep the container outside the terminal — at your warehouse for unloading — beyond the allowed free time before returning the empty.

A simple way to remember it: demurrage is the box waiting inside the port; detention is the box being held outside it.

How free time works

Carriers grant a number of free days — often a handful — for each side: free time to collect the full container, and free time to return the empty. Beyond that, charges accrue per container, per day, usually on a rising scale that gets steeper the longer you go. On a multi-container shipment, those daily charges multiply quickly.

Why importers get caught out

Customs delays — if clearance is not ready when the container lands, demurrage starts ticking.
Slow unloading — if your warehouse cannot turn the container around quickly, detention builds.
Empty return problems — congested depots or missed return appointments extend detention.
Documentation issues — a B/L not released or paperwork queried can hold the box at the port.

How to avoid them

Clear customs in advance. Have documents ready and clearance arranged before the vessel arrives, so the container can move the moment it lands.
Plan unloading. Book labour and dock time so the container is emptied and returned within free time.
Know your free days. Ask your forwarder how many you have on each side, and work back from there.
Negotiate more free time. On regular or large shipments, extended free time can sometimes be arranged up front — far cheaper than paying daily charges.
Return empties promptly and confirm depot appointments to avoid last-mile detention.

Frequently asked questions

What is the difference between demurrage and detention? Demurrage is the box waiting inside the port — a full container left at the terminal past the free time before pickup. Detention is the box held outside the port — keeping the container at your warehouse past the free time before returning the empty.

How much free time do I get? Carriers typically grant a handful of free days on each side — to collect the full container and to return the empty. The exact number varies by carrier and lane, so ask your forwarder how many you have on each side and plan back from there.

How are the charges calculated? Per container, per day, usually on a rising scale that gets steeper the longer you go. On a multi-container shipment the daily charges multiply quickly.

How do I avoid demurrage and detention? Clear customs before the vessel arrives so the container can move the moment it lands, book labour and dock time to unload within free time, return empties promptly with confirmed depot appointments, and on regular or large shipments negotiate extended free time up front.

The bottom line

Demurrage and detention are almost always preventable with preparation: clear customs early, unload promptly, and know your free time. A good forwarder watches these clocks for you and flags a container at risk — but the fastest way to avoid the charges is to have everything ready before the box arrives. For the broader picture, this guide forms part of our guide to air and ocean freight from China.