Demurrage and detention: what they are and how to stop paying them

Of all the surcharges that eat into a file’s margin, few hurt like demurrage and detention: they show up at the end, when you thought the job was closed, and almost always they could have been avoided. Understanding the difference is the first step to stop paying them.

Demurrage vs detention, no confusion

Both are time-based charges, but they measure different things:

• Demurrage: charged by the carrier when the full container stays at the port terminal beyond the agreed free days. The clock runs from discharge until you pick it up.
• Detention: charged by the carrier when the container is outside the terminal (already picked up) and isn’t returned empty on time. The clock runs while the container is in your hands.

Quick rule: demurrage = inside the port, detention = outside the port. In some trades they combine with port storage, charged by the terminal itself (not the carrier) for occupying the quay.

Why they pile up

Most of the time it’s not carelessness, it’s a lack of timely information:

1. You don’t know the vessel has berthed. Free days start counting and no one has told the customs team or the haulier.
2. Clearance gets stuck. A missing document holds the container at the port, adding demurrage day after day.
3. The empty return is forgotten. The container sits at the client’s premises and detention runs while no one is watching.

In all three cases the problem is the same: the data arrives late.

How visibility avoids them

When you see the vessel’s real position and events flow in on their own, the game changes:

• You know in advance when it will berth and prepare clearance and pickup before the free days start counting.
• You get alerts when a container approaches its free-day limit, at port or in detention, and act before the charge is generated.
• You have each container’s milestones in one place, so the team doesn’t depend on someone logging into the carrier’s website.

It’s not magic: it’s bringing the information forward a few days. But those days are exactly the difference between paying demurrage and not paying it.

What to look for to reduce them

• Does your system alert you before the free days run out, or do you find out with the invoice?
• Do you see the vessel’s real ETA, or just the one the carrier published days ago?
• Are each container’s milestones visible to the whole team, or scattered across emails?

Rowan Cargo recalculates the ETA from the vessel’s AIS and alerts you when a container approaches its limit, so demurrage and detention stop being a surprise on the invoice. Want to see it with your trades? Book a demo.