Demurrage and detention (often shortened to D&D) are among the most disputed charges in container shipping. They are rarely large per day, but they accumulate quickly and often arrive after the shipment is closed. Understanding exactly what each covers is the first step to controlling them.
Three different charges
| Charge | Where the container is | Levied by | What it compensates |
|---|---|---|---|
| Demurrage | Inside the terminal, full (import) or awaiting loading (export) | Shipping line | Use of the line's container beyond free time in the terminal |
| Detention (per diem) | Outside the terminal, with the shipper or consignee | Shipping line | Use of the container beyond free time outside the terminal |
| Port storage | Inside the terminal | Terminal operator | Use of terminal space beyond the terminal's free period |
Some lines combine demurrage and detention into a single merged free time, which gives the importer flexibility to split the days between terminal and premises. Terminology is not fully standardised across regions, so always read the tariff and the booking terms.
How free time is counted
Free time is set by the carrier's tariff or negotiated in the service contract. Key details that change the outcome:
- Start point: for imports, usually from discharge or availability; for detention, from gate-out of the full container.
- Calendar or working days: whether weekends and public holidays count.
- End point: for detention, the return of the empty container to a designated depot, which may not be the depot nearest to you.
- Tiered rates: daily charges often rise after the first few chargeable days.
Why charges build up
The underlying causes are usually process failures rather than bad luck:
- Documentation not ready at arrival, for example an original bill of lading still with the bank, or a missing certificate delaying customs.
- Customs examination or holds, especially where classification or valuation is queried.
- No delivery slot or receiving capacity at the consignee's warehouse.
- Empty return problems: depot congestion or designation of a distant depot.
- Transshipment and schedule changes that bunch arrivals.
The World Bank's Logistics Performance Index includes import dwell time data by country, which is useful for setting realistic expectations for clearance lead times on a new lane.
Regulatory attention
Regulators have scrutinised D&D practices, particularly after the congestion of 2021–22. In the United States, the Ocean Shipping Reform Act of 2022 and the Federal Maritime Commission's subsequent billing rule set requirements for how demurrage and detention invoices are issued and what information they must contain, and allow them to be challenged. Other jurisdictions address D&D through port or competition regulation. Regardless of jurisdiction, keep records of availability notices, appointment attempts and depot refusals; they are the evidence for any dispute.
Controlling D&D in practice
- Negotiate free time up front. For regular lanes, extended free time in the contract is often worth more than a small rate reduction.
- Pre-clear where possible. Lodge customs documents before arrival and resolve classification questions in advance; see our HS classification guide.
- Release documents early. If payment is by letter of credit, allow for bank processing time before arrival; see letters of credit and shipping documents. A sea waybill or telex release avoids the wait for original bills where the payment structure allows.
- Book delivery and empty return together. Know the designated return depot before the container is collected.
- Track actual events. Container milestone data built on standards such as those from the Digital Container Shipping Association makes free-time clocks visible rather than estimated.
- Audit invoices. Check start and end events, calendar rules and rates against the tariff or contract.
For base oil and other liquid cargo, testing and discharge scheduling add further time at destination; see our guide to shipping base oil from the UAE to India.
Frequently asked questions
What is the difference between demurrage and detention?
Demurrage is charged by the shipping line for keeping its container inside the terminal beyond free time. Detention is charged for keeping the container outside the terminal, at your premises or in transit, beyond free time.
Is port storage the same as demurrage?
No. Port storage is charged by the terminal operator for occupying terminal space. It can apply at the same time as the shipping line's demurrage.
How can I reduce demurrage and detention charges?
Negotiate adequate free time, prepare customs documents before arrival, release bills of lading early, plan delivery and empty return together, and audit invoices against the agreed terms.
References
- U.S. Federal Maritime Commission, fmc.gov (Ocean Shipping Reform Act of 2022 and demurrage and detention billing requirements).
- World Bank, Logistics Performance Index.
- UNCTAD, Review of Maritime Transport.
- Digital Container Shipping Association, track-and-trace and event standards.
Prepared by the Apex Ocean Lines industry experts and editorial team, checked against the sources cited. Short forms link to our shipping glossary.