Demurrage and Detention: A Shipper's Guide to Avoiding the Hidden Bill

Demurrage and detention are the charges that never appear on the original quote and somehow always appear on the final invoice. They are also among the most avoidable costs in container shipping — once you understand exactly what you are being billed for.

Two charges, two clocks

The terms are often used interchangeably, but they measure different things. Demurrage accrues when a full container sits inside the terminal beyond its free days, waiting to be picked up. Detention accrues when you keep the carrier's container outside the terminal beyond its free time, typically while you unpack it. One clock runs at the port; the other runs at your yard.

Where the days disappear

Most D&D is generated by a handful of predictable failures: customs clearance that was not pre-filed, so the box sits while paperwork catches up; trucking that was not arranged before arrival; or an unpacking operation that runs slower than the free-time allowance. None of these are shipping problems — they are coordination problems.

Demurrage is rarely a freight failure. It is almost always a planning failure that happens to show up on the carrier's invoice.

Cutting the bill

• Pre-file customs so release is waiting when the vessel berths, not days later.
• Stage trucking against the actual ETA, with a buffer for berth slippage.
• Negotiate free time up front on high-volume lanes — extra days are cheaper bought in the contract than at the gate.
• Watch the clock with milestone alerts so a slipping deadline is visible while you can still act on it.

The charge is designed to keep equipment moving. Treat it as a coordination KPI, not a fee, and most of it disappears.

References

• US Federal Maritime Commission (FMC)
• UNCTAD — Review of Maritime Transport