Demurrage vs detention: the two clocks, explained properly
The difference between demurrage and detention in container shipping — when each clock starts and stops, typical rates, why the two get confused, and why that confusion appears on invoices.
Two charges, two clocks
Demurrage is the charge for your container sitting inside the terminal after your free days run out. The clock starts when the container is discharged from the vessel and stops when it gates out of the terminal. Typical triggers: customs holds, congestion, late paperwork, no trucking capacity.
Detention (sometimes 'per diem') is the charge for keeping the carrier's container outside the terminal beyond its free days — you're renting their box. The clock starts at gate-out and stops when the empty is returned. Typical triggers: warehouse backlogs, chassis shortages, slow unloading.
A single shipment can incur both, sequentially — and one of the classic billing errors is incurring both simultaneously, with the two charges overlapping the same calendar days. That overlap is disputable.
What it costs
Rates escalate in tiers. As an indicative shape: £75–£150 per container per day for the first few days over, doubling in later tiers to £300+ per day. A container stuck two weeks through a customs examination quietly becomes a £2,000–£4,000 invoice — per box.
Industry-wide, demurrage & detention leakage is measured in the tens of billions of dollars annually, and 20–30% of charges are overturned when disputed with evidence (a figure that emerged from US FMC-era data after OSRA 2022 forced carriers to justify charges on standardised invoices).
Why the confusion matters
Because the two clocks have different start events, mislabelling one as the other changes the day count. Demurrage billed from vessel arrival rather than container discharge, or detention billed from discharge rather than gate-out, each silently add days you never owed. Checking the invoice's clock start against the terminal's own timestamps is the first move of any audit — it's mechanical, which is why software does it better than a busy ops team.
Frequently asked
Can I be charged demurrage and detention at the same time?
Not for the same days, under most contracts — demurrage covers the box inside the terminal and detention outside it. Overlapping charges on the same calendar days are one of the most commonly won disputes.
Who pays demurrage — the forwarder or the importer?
Commercially it lands on whoever controls the cargo at that stage, usually the importer/consignee; forwarders typically pass carrier charges through. Either way, the party paying has the right to dispute an incorrect invoice.
Is storage the same as demurrage?
No — terminals may charge their own storage/quay rent separately from the carrier's demurrage. Check you're not paying twice for the same days under two labels.
Find out what your last quarter owes you
Marevo reads your invoices against your contracts and the terminal data, drafts the disputes, and is paid mostly from what actually comes back. The audit itself is free.
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