Demurrage is charged when a full container stays inside the port terminal beyond the free time granted. Detention is charged when the container is outside the terminal, at the consignee’s site or in transit, beyond free time, until the empty is returned. Together they are known as D&D or dem/det charges; storage charges, by contrast, pay for the use of terminal space.
These three charges are often confused on an invoice, yet they depend on different events and sometimes on a different issuer. To understand them, you need three things: the contract, the event dates and the applicable tariff.
Demurrage vs detention vs storage
Maersk’s terms give representative definitions: demurrage compensates for holding a container inside the terminal, port or depot beyond free time; detention for holding it outside; storage for using the facilities beyond free time. The same terms also provide a combined option covering the whole period, inside and outside. The US Federal Maritime Commission (FMC) draws the same line: detention covers extended use of the equipment, demurrage covers exceeding free time at the terminal (FMC).
| Charge | Where the container is | Clock starts (import) | Clock stops (import) | Who bills |
|---|---|---|---|---|
| Demurrage | Inside the terminal, full | Discharge from the vessel | Gate-out of the full container | The shipping line |
| Detention | Outside the terminal | Gate-out of the full container | Empty returned to the designated depot or terminal | The shipping line |
| Combined D&D | Inside, then outside | Discharge from the vessel | Empty returned | The shipping line |
| Storage | Inside the terminal | Per terminal terms | Gate-out | Depends on the port: terminal or line |
The table describes an import. For exports, the logic reverses. Under the combined formula, the period starts when the empty container leaves the depot and ends when the full container is loaded on board. When the charges are split, detention runs from empty pick-up until the full container is gated in at the terminal, then demurrage runs until loading on board (Maersk).
The events that start and stop the clock vary by carrier. At Maersk, for example, when the container moves to an inland depot, the clock starts when the full container is gated in at that depot.
Detention charges
Detention runs while the container is outside the terminal: road or rail haulage, waiting to be unloaded, unloading, then the empty return. It stops when the empty is returned to the place designated by the line, which may be an inland depot or a port terminal.
Detention days = empty return date − terminal gate-out date, minus detention free time.
A container delivered on time can still incur detention if it is not unloaded and returned quickly, or if the return depot has no slot available.
Demurrage charges
Demurrage runs after the container is discharged, for as long as it stays full inside the terminal. It encourages consignees to collect containers and free up port space. Typical causes are pending customs clearance, a missing document, unbooked trucking or a warehouse without receiving capacity.
Demurrage days = terminal gate-out date − discharge date, minus demurrage free time.
Storage charges
Storage pays for the use of terminal space. Depending on the port, the terminal operator bills it on top of the line’s demurrage, or it is not billed separately. Maersk, for example, states that separate storage invoicing is set country by country (Maersk). Check who issues it and from when, port by port.
How free time works
Free time is the period during which these charges are not due. It depends on the line, the country, the port, the equipment type (dry, reefer, out of gauge) and your contract. Lines publish their tariffs, and Maersk refers to its published tariffs for the compensation due (Maersk).
Three points change the result:
- Combined or separate free time. Combined free time covers the whole period from discharge to empty return; separate free time is counted on one side for demurrage and on the other for detention.
- Calendar or working days. Depending on the terms, weekends and public holidays are counted or not. Unless the terms say otherwise, assume they count and ask for confirmation.
- Progressive bands. The daily rate can increase in steps after free time. Note the bands in your tariff.
Hypothetical example
A container stays 7 days in the terminal after discharge, then 2 days at the consignee before the empty is returned.
- With combined free time of 10 days: 9 days in total, nothing to pay.
- With separate free time of 5 demurrage days and 5 detention days: 2 billable demurrage days, no detention.
Same total duration, different outcome: the structure of free time matters as much as its length.
How to reduce demurrage and detention
- Ask for free time at booking. Have your forwarder state the free time attached to each quote, combined or separate, and compare quotes on equal free time.
- Negotiate free time. Depending on the period and volumes, extra days can be discussed with the forwarder or the line.
- Prepare the arrival before discharge. Documents, customs clearance, trucking and a receiving slot at the warehouse.
- Plan the empty return. Check the designated depot and its availability: delivery does not end container management.
- Keep evidence of dates. Gate-out, delivery, empty return: a one-day discrepancy can change the amount.
In OneChain, transport management and warehouse scheduling provide context for coordinating these steps. Invoice control then helps compare charges with available references. To follow free-time deadlines, see also proactive tracking of containers at risk of D&D charges.
Frequently asked questions
What is the difference between demurrage and detention?
Demurrage applies when the full container stays inside the terminal beyond free time. Detention applies once the container has left the terminal and is not returned empty in time. Both are billed by the shipping line, sometimes under a combined free time.
What are demurrage fees?
Demurrage fees are daily charges billed by the shipping line for each day a full container remains in the terminal after free time expires. The rate depends on the line’s published tariff for the port, the equipment type and your contract.
Who pays demurrage and detention charges?
Incoterms do not expressly cover these charges. The Incoterm says who arranges carriage at destination; the sales contract and the forwarder’s quote specify who bears demurrage and detention, which the forwarder often re-invoices. Check your quote.
Are weekends included in free time?
It depends on the line’s terms and your contract: free time can be expressed in calendar days, including weekends and public holidays, or in working days. Without a written rule, assume weekends count and ask your forwarder at booking.
Can you dispute a demurrage or detention invoice?
Yes, by comparing the invoiced dates with gate-out, delivery and empty-return evidence and with the contractual free time. In the US, the Ocean Shipping Reform Act of 2022 provides that an invoice lacking the required information does not have to be paid (Public Law 117-146). The FMC rule in force since May 2024 also sets deadlines for invoicing and disputes (FMC).
What is the difference between demurrage and storage?
Demurrage compensates the shipping line for the use of its container. Storage pays for the use of terminal space and may be billed separately, depending on the port.