Few invoices frustrate a forwarding team more than a demurrage bill. The container arrived, the cargo was fine, and yet a few days of waiting in the terminal added a charge the customer did not expect and does not want to pay.
Many demurrage charges can be prevented or reduced with earlier action and tighter shipment visibility. They often come from a small number of predictable causes, and each cause has a practical control that reduces the risk. This guide explains what demurrage is, how it is charged, what US billing rules say, and the steps ops teams use to keep containers out of the charge window.
What are demurrage charges?
Direct answer: For U.S. ocean imports, demurrage charges are fees an ocean carrier or marine terminal assesses when a full container remains at the terminal after its free time ends. After the last free day, charges may accrue per container per day under the applicable tariff, terminal schedule, service contract or negotiated arrangement, often at rates that increase over time.
Demurrage is about the container sitting at the terminal. It is different from detention (sometimes called per diem), which applies when the container has left the terminal and is not returned on time. Some ports also use the word "storage" for the terminal's own charge. The terminology varies, so it is worth reading the carrier's and terminal's tariffs for the ports you use.
How are demurrage charges calculated?
The calculation has three parts:
- Free time. A set number of days, counted from when the container is discharged or becomes available. It is defined in the carrier's or terminal's tariff, or in your service contract if you negotiated extra days.
- The last free day. The final day of free time. Whether weekends and public holidays count depends on the tariff. See our guide to last free day (LFD) in shipping.
- Daily rates. Charges per container per day after the last free day, often in tiers that increase after a set number of days. Rates vary by carrier, terminal and container type.
Because every carrier and terminal sets its own terms, the same delay can cost very different amounts on two shipments arriving the same day.
Why do demurrage charges happen?
Demurrage often traces back to one of these causes:
- Late or incomplete documents. The pre-alert is missing a document, or the details do not match, so customs filing or freight release is delayed.
- Customs holds or exams. The goods are not released in time. Charges may continue under the applicable tariff or terminal schedule, but do not assume the clock always runs or always stops; the reasonableness of charges during a government inspection depends on the circumstances.
- Unpaid charges or bill of lading issues. Freight release waits on payment, the original bill, or a telex release.
- No truck or appointment. The container is released, but no trucker is booked or terminal appointments are full.
- A moved last free day nobody noticed. The vessel arrived early or late, the discharge date changed, and the pickup plan was built on the old date.
- Congestion and closures. Terminal congestion, chassis shortages or closures make pickup harder, even when everything else is ready.
Congestion and customs exams are largely outside the team's control. Many of the remaining causes are visibility and timing problems that earlier action can reduce.
Who pays demurrage charges?
Who receives a demurrage invoice—and who ultimately bears the cost—depends on the applicable contract, tariff or terminal schedule, and the facts of the shipment. A forwarder or NVOCC may pass through a properly supported charge to its customer when the customer agreement allows it. Because former 46 CFR §541.4 was set aside in 2025, do not rely on that section to determine the proper billed party.
What do US rules say about demurrage invoices?
In the United States, demurrage and detention billing is covered by the Federal Maritime Commission's rules in 46 CFR Part 541. Three timelines are especially useful for ops teams:
- Except for the NVOCC pass-through timing below, invoices must be issued within 30 calendar days of the date the charge was last incurred. If they are not, the billed party is not required to pay the charge.
- An NVOCC passing on a charge has 30 calendar days from the date of the invoice it received to issue its own invoice.
- The billed party must get at least 30 calendar days from the invoice date to request mitigation, refund or waiver. The billing party must attempt to resolve the request within 30 calendar days of receiving it, or by a later date agreed to by both parties.
That makes two habits valuable: recording the actual pickup and return dates on every shipment, and checking each demurrage invoice against those dates and the invoice date as soon as it arrives. On September 23, 2025, the D.C. Circuit set aside 46 CFR §541.4, which had specified who could be billed. The FMC removed that section effective December 29, 2025; the remaining provisions of Part 541 remain in effect.
How can freight forwarders avoid demurrage charges?
These ten habits reduce demurrage risk:
- Chase complete pre-alerts early. Check that container numbers, bills and invoices match before the vessel arrives, not after.
- File customs early. Where your broker and the rules allow it, file the entry before arrival so release is ready at discharge.
- Clear freight release in advance. Collect payment and settle the bill of lading requirements before the container is available.
- Book the trucker before arrival. Line up the carrier and terminal appointment around the expected availability date.
- Track ETA and the last free day every day. Treat any ETA or discharge change as a trigger to re-plan pickup.
- Watch for holds. Customs and freight holds are a common reason a planned pickup fails.
- Tell the customer early. Share the last free day and what you still need from them in the arrival notice, and again when it moves.
- Negotiate free time. For regular lanes, extra free days in the service contract can be worth more than a small rate reduction.
- Review every demurrage invoice. Compare billed days with the real discharge, pickup and last free day dates.
- Dispute inside the window. Under the US rules above, you have at least 30 days from the invoice date to ask for a waiver or refund, so do not let invoices sit.
Most of these are not hard. They fail because the information arrives in scattered emails and portal updates, and because nobody has time to re-check every container every day.
How does automation help reduce demurrage?
The biggest gains come from never losing sight of the dates. An AI teammate can read carrier and terminal updates as they arrive, keep the ETA, availability and last free day current on each shipment, and flag containers that are approaching their free time without a release or pickup plan. It can also link demurrage invoices to the right shipment and highlight days that do not match the recorded dates.
The decisions still belong to people: whether to pay for an expedited pickup, how to split a charge with a customer, or when to dispute. Automation makes sure those decisions happen days before the deadline, not the day after.
Where NavLogic fits
NavLogic is the AI teammate built for freight operations. For ocean imports it monitors ETA, holds, last free day and empty return across carrier updates, prepares arrival notices that tell customers what is due and when, and reads carrier and D&D invoices so each charge is linked to the right shipment. Exceptions come to the right operator with the emails and documents attached.
Frequently asked questions
What is the difference between demurrage and detention?
Demurrage is charged while a full container stays in the terminal after its free time. Detention, often called per diem, is charged when the container has left the terminal and is not returned within its own free time. A single shipment can incur both.
Can demurrage charges be waived?
Sometimes. Carriers and terminals may reduce or waive charges, for example when the delay was caused by the carrier or terminal. In the US, you must be given at least 30 days from the invoice date to request a mitigation, refund or waiver.
Does demurrage run during a customs hold?
Not automatically. Charges may continue during a customs hold under the applicable tariff or terminal schedule, but the FMC evaluates reasonableness in light of the incentive principle, government inspections and the specific circumstances. Check the governing terms and document when the container was unavailable.
How many free days do you get before demurrage?
It depends on the carrier, terminal, container type, tariff and any negotiated terms. There is no universal number. Confirm the exact free time for each shipment in the applicable tariff, terminal schedule or service contract.
Who is responsible for paying demurrage?
Who receives the invoice and who ultimately bears the cost depend on the applicable contract, tariff or terminal schedule, and the facts of the shipment. A forwarder or NVOCC may pass through a properly supported charge when its customer agreement allows it.
How late can a demurrage invoice be issued in the US?
Under 46 CFR §541.7, a billing party generally must issue a demurrage or detention invoice within 30 calendar days of the date the charge was last incurred. For an NVOCC passing through a charge, the 30-day period runs from the issuance date of the invoice it received. Missing the applicable deadline means the billed party is not required to pay the charge.
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