Demurrage and detention are among the most misunderstood costs in container logistics, and among the easiest to avoid with a little planning.
The two clocks
They are not the same charge, and they run on separate clocks:
- Demurrage accrues when a full container sits inside the port or CFS beyond the free period.
- Detention applies once the container leaves but is not returned empty in time.
The free days for each are set by the shipping line, not the port, so they vary line to line and contract to contract. Know your free days before the box lands.
How importers actually get billed
Most charges are not caused at the counter. They are caused by documentation that was incomplete before the ship arrived, so the container waits while paperwork catches up.
The single biggest lever
Coordinate early with your CHA so documentation is ready before the vessel berths. A container that clears on day one never starts either clock. Everything else, faster transport, better yard planning, helps, but nothing beats clearing before the free period runs out.
If demurrage keeps showing up on your invoices, it is usually a process problem, not a rate problem, and it is fixable.