What Are Demurrage and Detention? Extra Costs in Container Shipping and How to Avoid Them
Demurrage is the charge for a container waiting inside the port/terminal beyond its free time; detention is the charge for a container staying outside the terminal, at the customer's premises or warehouse, beyond its free time and for the empty container not being returned on time. Both are billed per container and per day, and can be prevented with early documentation, an accurate delivery plan, and on-time return.
In container shipping, demurrage and detention are two extra cost items that arise when free time is exceeded and are often confused with each other. Both penalize a container waiting beyond its allotted free time; however, demurrage concerns the excess time a container spends inside the port/terminal, while detention concerns the excess time it spends outside the terminal (at the customer's site or warehouse). This guide explains the concept of free time, the difference between demurrage and detention, import and export scenarios, the pricing logic, and how these costs can be prevented in practice.
What Is Free Time?
Free time is the free waiting/usage period that the carrier or the port grants for a container. During this period, no additional waiting charge accrues for the container waiting at the terminal or being used outside the terminal. The moment free time ends, the demurrage or detention counter starts running.
The length of free time is not fixed; it varies by carrier, port, shipping line, and contract terms. Although in practice free time is usually seen in the range of 7-14 days, the exact number of days should be confirmed for each shipment through the relevant carrier and contract.
Because free time can be defined separately for demurrage and detention, the start and end dates of both the in-terminal (demurrage) and off-terminal (detention) free times must be tracked separately for a given shipment. Accurately monitoring these dates is the first step to preventing extra costs.
What Is Demurrage?
Demurrage is the waiting charge paid to the carrier or the port when a container waits inside the port or terminal beyond the allotted free time. It applies as long as the container remains within the terminal boundaries; that is, the fact that the cargo has not physically left the terminal is the distinguishing feature of demurrage.
In imports, demurrage typically arises when the incoming laden container is not picked up from the port on time. In exports, leaving the laden container at the port long before vessel loading and letting it wait at the terminal for a long time can lead to demurrage. In both cases, the container has exceeded the free time inside the terminal.
Since demurrage is calculated per container and per day, each additional day spent at the terminal increases the cost. For this reason, completing the customs and delivery process within the free time forms the basis of preventing demurrage.
What Is Detention?
Detention is the charge paid when a container stays beyond the allotted free time outside the terminal - at the customer's facility, warehouse, or during transport. In essence, it covers the container (especially the empty container after unloading) not being returned to the carrier on time.
In imports, detention arises when the empty container is not returned to the carrier on time after the laden container has been picked up from the port and unloaded. In exports, detention arises when the container taken empty from the depot for stuffing (filling the container) is not delivered back to the port on time after loading.
Unlike demurrage, detention covers the period after the container leaves the terminal. Therefore, structuring the unloading, filling, and return plan according to the free time is decisive in preventing detention.
Demurrage and Detention in Import and Export Scenarios
In an import scenario, the process is two-staged: the container first waits at the terminal (demurrage risk), then after being picked up and unloaded it is returned empty (detention risk). If the incoming laden container is not picked up from the port within the free time, demurrage arises; if the empty container is not returned on time after pickup, detention arises.
The export scenario is like a mirror image of this: the exporter takes the empty container for stuffing (its late return falls under detention), the filled laden container is left at the port and waits at the terminal until vessel loading (its early and long waiting falls under demurrage). In other words, both demurrage and detention can arise at different stages within the same shipment.
Some lines may, in a merchant haulage scenario (where the transport arrangement is on the cargo owner's/forwarder's side), also apply demurrage and detention together as a single 'combined demurrage & detention' item. In this case, even though the two items are merged into a single invoice, the logic is the same: exceeding free time is charged per container and per day.
Extra Costs, Pricing, and Transparency
Demurrage and detention are billed per container and per day. Pricing usually works on a tiered/increasing tariff logic: the first days are relatively lower, and the charge increases on subsequent days. Since the exact amounts vary greatly by carrier, port, and container type, they should be confirmed from the relevant carrier's tariff for each shipment.
These items are paid by the cargo owner (importer or exporter). The freight forwarder, as the party coordinating the process, reduces the risk with the documentation, delivery, and return plan; however, the party liable for the final cost is the cargo owner. For this reason, knowing the free time dates and possible extra costs from the outset prevents surprise invoices.
Forwardie sets up the delivery plan according to free time and tries to prevent these costs by preparing documents in advance; items such as demurrage and detention are transparently stated in its quotations. This way, the cargo owner can see in advance by which date they need to act and what the possible extra cost items are.
Demurrage — Detention
| Demurrage | Detention |
|---|
| Definition | The charge paid to the carrier/port when a laden container waits inside the port/terminal beyond the allotted free time. | The charge paid when a container stays outside the terminal (at the customer's site/warehouse) beyond the free time, and when the empty container is not returned to the carrier on time. |
| Container location | Waits within the port/terminal boundaries. | Outside the terminal; remains at the customer's facility, warehouse, or during transport. |
| Which situation it penalizes | The container not being picked up from the terminal on time, or in exports being left at the terminal long before vessel loading and waiting there. | The container being held outside the terminal too long and the empty container not being returned on time. |
| When the counter starts | Starts running when the allotted free time expires while the container is inside the terminal. | Starts running when the allotted free time expires while the container is outside the terminal. |
| Typical trigger | In imports, the incoming laden container not being picked up from the port on time; in exports, the laden container being left at the port long before vessel loading. | In imports, the empty container not being returned on time after unloading; in exports, the container taken empty from the depot for stuffing not being delivered back to the port on time after loading. |
| Who pays | The cargo owner (importer/exporter); the freight forwarder coordinates the process. | The cargo owner (importer/exporter); the freight forwarder coordinates the process. |
| How to prevent it | Preparing customs documents before the vessel arrives and planning to pick up the container from the terminal within the free time. | Scheduling unloading and empty return within the free time and returning the container on time by appointment. |
Step by step
- Prepare customs documents before the vessel arrives: Prepare the import declaration, bill of lading, invoice, and all required documents before the container reaches the terminal; if possible, bring the customs process forward with customs pre-clearance. This way the container can be picked up within the free time and the demurrage risk is reduced.
- Set up the delivery and unloading plan according to the free time: Plan the time needed to pick up, transport, and unload the container so that it fits within the free time. Instead of leaving the unloading date to the last day of the free time, allow a buffer margin.
- Plan the empty container return in advance and book an appointment: Determine from the outset where and when the empty container will be returned after unloading; book the return appointment in advance if needed. On-time return is one of the direct ways to prevent detention.
- Track the free time end dates: Closely monitor the start and end dates of the free times, which can be defined separately for demurrage and detention. Seeing approaching end dates early lets you take action before a delay occurs.
- Negotiate a longer free time if necessary: If the nature of the cargo, the customs process, or warehouse conditions require a long wait, negotiate a longer free time with the carrier at the booking stage. Extra time secured upfront is more manageable than an extra cost that arises later.
- Account for port/warehouse congestion and public holidays: Terminal and warehouse congestion, appointment scarcity, and public holidays can extend unloading and return times. Prevent exceeding the free time by buffering the plan against these real-world delays.
Frequently Asked Questions
What is the difference between demurrage and detention?
Demurrage is the charge for a container waiting inside the port/terminal beyond the free time. Detention is the charge for a container staying too long outside the terminal (at the customer's site/warehouse) and for the empty container not being returned to the carrier on time. In short, demurrage concerns in-terminal waiting, while detention concerns off-terminal waiting.
How many days is free time?
Free time is not fixed; it varies by carrier, port, shipping line, and contract. Although in practice it is usually seen in the range of 7-14 days, the exact number of days should be confirmed for each shipment through the relevant carrier and contract.
How are demurrage and detention charges calculated?
Both charges are calculated per container and per day. A tiered/increasing tariff is usually applied: the first days are charged lower, and subsequent days higher. Since the exact amount varies greatly by carrier, port, and container type, it should be confirmed from the relevant tariff.
Who pays the demurrage and detention charges?
These items are paid by the cargo owner (importer or exporter). The freight forwarder coordinates the process and reduces the risk with the documentation and delivery/return plan; however, the party ultimately liable for the invoice is the cargo owner.
What does 'combined demurrage & detention' mean?
Some shipping lines, especially in a merchant haulage scenario, may combine demurrage and detention and bill them as a single 'combined demurrage & detention' item. Even though the two items are merged into a single invoice, the logic is the same: exceeding free time is charged per container and per day.
Can a freight forwarder completely prevent demurrage and detention?
The forwarder significantly reduces the risk of these costs arising by preparing documents in advance and setting up the delivery and return plan according to the free time. However, due to external factors such as port congestion, customs processes, and public holidays, zero demurrage/detention cannot be guaranteed; the aim is to minimize the risk and report costs transparently.
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