In international container shipping, freight costs are just the tip of the iceberg. One of the most common reasons a deal's unit economics goes into the red is hidden port and carrier surcharges. The two biggest "nightmares" for any international trade participant are demurrage and detention.
These idle time penalties can amount to hundreds of dollars per day per container and are charged for literally just a few hours of delay. In this article, we will take a detailed look at the differences between these concepts, how free time is calculated, and how to structure your logistics so you never have to pay these penalties.
What is Demurrage?
Demurrage is a penalty for keeping a full or empty container inside the marine terminal (port) beyond the allotted free time.
Simply put: the container has arrived at the port and been discharged from the vessel, but you haven't managed to gate it out in time (e.g., customs clearance isn't finished, documents are delayed, or there aren't enough trucks for pick-up). A terminal is not a long-term storage facility; its space is limited. Therefore, the port or the carrier starts charging you for your cargo taking up space at the terminal.
Main causes of demurrage:
Delays in customs clearance (missing certificates, declaration errors, inspections).
Late payment of Terminal Handling Charges (THC).
Lack of arranged trucks or rail flatcars to move the cargo out of the port.
Delays in receiving original bills of lading or issuing a DO (Delivery Order).
What is Detention?
Detention is a penalty for keeping container equipment outside the marine terminal (at the consignee's warehouse, at a rail station, or in transit) beyond the allowed free time.
Simply put: you picked up the container from the port, brought it to your warehouse, but failed to unload it and return the empty container to the port or the shipping line's depot within the allotted time. The carrier (shipping line) leases its equipment to you. If you hold onto it for too long, the line loses the opportunity to use that container for other shipments and bills you for detention.
Main causes of detention:
Long loading/unloading times at the customer's warehouse (staff shortages, forklift breakdowns).
Queues for returning empty containers to the line's depot.
Delays in inland transportation (truck breakdowns, rail delays, weather conditions).
Delays in returning documents (EIR — Equipment Interchange Receipt).
The Main Differences Between Demurrage and Detention
To remember the difference once and for all, use this simple rule:
Demurrage = the container is IN the port (penalty for occupying space).
Detention = the container is OUTSIDE the port (penalty for equipment usage time).
Parameter | Demurrage | Detention |
Where is the container? | Inside the marine terminal / port | Outside the port (at a warehouse, in the city, in transit) |
What is the charge for? | Storing the cargo and occupying terminal space | Using the line's equipment (the container itself) |
Who issues the invoice? | The marine terminal or the carrier | The shipping line, the container owner |
Typical causes | Customs issues, document problems, lack of trucks for pick-up | Long unloading times at the warehouse, delays in returning empty equipment |
Note: Sometimes another concept is distinguished — Port Storage. This is a fee charged by the terminal itself for the use of its space, regardless of the shipping line. However, in practice, importers most often deal with carrier demurrage and detention.
What is Free Time and How Does It Work?
Free time is a grace period granted by the shipping line or terminal to the customer for processing documents, picking up the container from the port, unloading it, and returning the empty equipment.
Typically, standard free time ranges from 3 to 7 days. However, at the booking stage, a competent freight forwarder always requests extended terms from the line:
14 free days (a standard request for most routes).
21 free days (often requested for complex routes, e.g., with transshipment or rail dispatch to inland regions).
Combined D&D (a combined pool of days). Some lines offer, for example, 21 days in total for demurrage and detention, and the customer decides how to allocate them.
Important: Free time calculation starts at 00:00 on the day following the day the container is discharged from the vessel onto the terminal (for demurrage) or from the moment the container is gated out of the terminal (for detention). Weekends and public holidays are included in free time in most ports worldwide and do not extend it!
5 Ways to Avoid Idle Time Penalties
Demurrage and detention penalties usually follow a progressive scale: the longer the container sits, the more expensive each subsequent day becomes. How can you protect your profit margin?
Request extended Free Time at the booking stage.
Never settle for the standard 3-5 days if you are shipping from China, India, or the Middle East. Ask the line for 14 or 21 days. It costs nothing at the approval stage but can save thousands of dollars in the event of a vessel delay or customs issues.
Prepare documents before the vessel arrives.
Start the customs clearance process (filing the customs declaration) using scanned documents before the ship even docks. Use the advance information procedure.
Use off-dock terminals (bonded warehouses and dry ports).
If you realize you won't be able to release the cargo at the port in time, it is more cost-effective to arrange an internal customs transit procedure and move the container to a nearby bonded warehouse or partner dry terminal (for example, to the facilities of My Containers partners). Storage and handling rates outside the marine terminal are significantly lower than punitive demurrage rates.
You can view container storage options in key regions of China on this page: https://ru.my-market.mg/container-terminals-china-list
Book trucks in advance.
The truck must be ready to enter the terminal on the day the Release Order is received. Due to terminal queues, the truck's "time slot" might expire, and you could incur a full day of demurrage simply due to a logistical mismatch.
Return empty containers promptly.
As soon as the cargo is unloaded at your warehouse, immediately send the truck to the line's depot. Do not use a shipping container as a "warehouse on wheels" — it is cheaper to rent a stationary warehouse or buy/lease your own container.
You can view container purchase rates on our website: https://ru.my-market.mg/sale-containers
Why My Containers is Your Reliable Partner in Container Equipment Management
Working with international shipping requires strict timing control. My Containers helps clients minimize the risk of demurrage and detention charges:
Direct contracts with shipping lines: We request and secure extended free time on key routes from Asia. If you lease containers from us, we will provide extended free time.
Network of partner terminals: If cargo gets stuck at the port, we quickly arrange its transfer to our partner facilities (including dry ports and bonded warehouses), where storage rates are much lower than port penalties.
Container sales: If you need to store cargo for an extended period, we offer the purchase of your own containers, which completely eliminates the concept of carrier detention, as well as container storage services at facilities near key terminals in China.
*The information on this page does not constitute a public offer.
*My Containers is a partner of My Way.