Demurrage vs detention vs per diem: container charges in drayage

Five charges, three different owners

A container on a drayage move touches property that belongs to at least three parties: the marine terminal or rail ramp where it sits, the shipping line that owns or leases the box, and whoever supplies the chassis it rides on. Each of them charges for time once its free period ends, and each charge has its own clock, its own free time and its own terms. Most billing arguments in drayage start because two of these clocks are confused, or because one party is charging for time its own operation caused.

The names are not used the same way everywhere. Some lines combine demurrage and detention into a single charge, and some customers say "detention" for the waiting time a driver spends at their own dock. The FMC rule settles the vocabulary for its purposes: in 46 CFR 541.3, demurrage or detention means any charge, including "per diem" charges, assessed by an ocean common carrier, marine terminal operator or non-vessel-operating common carrier for the use of marine terminal space or shipping containers, but not freight charges.

When each clock starts and stops

Imports

Demurrage free time on an import usually starts when the container is discharged and available, and runs out on the last free day. If the box is still on terminal land after that day, demurrage accrues until it leaves the gate. The FMC rule requires the invoice to show both the container availability date for an import and the start and end dates of free time (46 CFR 541.6(b)), because availability is where most arguments begin: a box that is under a hold, buried in a stack or behind a terminal with no appointments is not available in any practical sense.

Detention or per diem starts when the loaded box leaves the terminal and runs until the empty is returned to a location the line accepts. A container can pick up both charges on one move: demurrage while it waits at the terminal past its last free day, then detention once it is out and the customer holds it too long.

Exports

On an export the order reverses. The empty leaves a depot or terminal and the equipment clock starts; the loaded box comes back to the terminal for its vessel. Terminals publish an earliest return date for each sailing, and an export delivered before it may sit as storage or demurrage. The invoice rule requires the earliest return date for exports (46 CFR 541.6(b)(7)).

What stops the clock

• Out-gate from the terminal stops demurrage. Keep the gate ticket or equipment interchange receipt.
• In-gate of the empty at a location the line has designated stops detention or per diem. If the terminal will not accept the empty, the clock does not stop by itself; that is the situation the FMC's interpretive rule addresses below.
• Return of the chassis stops chassis rental, and only that charge.

Free time is a contract term, not a federal number

There is no federal free-time allowance for containers. Free days come from the terminal's schedule, the shipping line's tariff, the service contract between the line and the shipper, or the drayage carrier's agreement with its customer, and they vary by port, line, equipment type and contract. Whether weekends and holidays count also depends on that document. What the FMC rule does is make the number visible: an invoice must state the allowed free time in days and the dates it started and ended (46 CFR 541.6(b)(3) to (5)), and the applicable rule or contract section on which the daily rate is based, with the specific rate (541.6(c)).

For a dispatcher this means reading the actual terms for each line and terminal you work with, and recording the free days and the last free day on each container rather than assuming a default. A drayage carrier that quotes its customer free time it does not get from the line ends up paying the difference.

What the FMC billing rule requires

46 CFR part 541 applies to any invoice issued by an ocean common carrier, marine terminal operator or non-vessel-operating common carrier for demurrage or detention (541.2(a)). It does not govern billing between ocean carriers and marine terminal operators (541.2(b)). A railroad billing ramp storage and a chassis provider billing rental are not among the three billing parties the rule names, so their charges follow their own tariffs and agreements. Neither is a drayage carrier invoicing its own customer: what you pass through is governed by your rate confirmation or contract.

Invoice contents

Under 46 CFR 541.6 a demurrage or detention invoice must include, at a minimum:

• Identifying information: the bill of lading number, the container number, the port of discharge for imports, and the basis for why the billed party is the proper party and liable for the charge.
• Timing information: the invoice date and due date, the free time in days, the start and end dates of free time, the container availability date for imports, the earliest return date for exports, and the specific dates charged.
• Rate information: the total due, the tariff rule, terminal schedule, service contract section or negotiated arrangement the daily rate is based on, and the specific rate or rates.
• Dispute information: a contact for questions or requests for mitigation, refund or waiver; a URL, QR code or similar pointing to a public page that lists what the billed party must provide; and the timeframes for requesting and resolving.
• Certifications that the charges are consistent with the FMC's demurrage and detention rules, including 46 CFR 545.5, and that the billing party's own performance did not cause or contribute to the charges.

The consequence is stated plainly in 541.5: failure to include any of the required minimum information eliminates any obligation of the billed party to pay the applicable charge.

Deadlines

• Issue: within 30 calendar days from the date the charge was last incurred; otherwise the billed party is not required to pay (541.7(a)). An NVOCC passing on a charge has 30 calendar days from the date of the invoice it received (541.7(b)). A corrected invoice to the right party must still go out within 30 days of the last charge (541.7(d)).
• Dispute window: the billing party must allow at least 30 calendar days from the invoice issuance date to request mitigation, refund or waiver (541.8(a)).
• Response: the billing party must attempt to resolve a request within 30 calendar days of receiving it, or later if both parties agree (541.8(b)).

When a charge is unreasonable

The FMC's interpretive rule at 46 CFR 545.5 explains how the Commission judges demurrage and detention practices. Its test is whether the charges serve their purpose as an incentive to keep freight moving. It says the Commission may consider whether demurrage and free time relate to cargo actually being available for retrieval, how and when notice of availability is given, and the circumstances of government inspections. It also says that, absent extenuating circumstances, detention charged when it does not serve that purpose, such as when empty containers cannot be returned, is likely to be found unreasonable (545.5(c)(2)(ii)).

How a drayage carrier disputes a charge

Most disputes are won or lost on records made at the time, not on arguments made later. A workable routine:

1. Check the invoice against 541.6. Are the bill of lading and container numbers right, are the free-time dates and availability date shown, and is the rate tied to a named tariff rule or contract section? A missing item is a complete answer under 541.5.
2. Check the dates against 541.7. Compare the invoice date with the last day the charge accrued.
3. Rebuild the timeline. Discharge or availability, holds placed and released, appointment attempts, out-gate, delivery, empty ready, return attempts and in-gate. Each step should have a time and a document: a gate ticket, a screenshot of an appointment system with nothing available, an email from the terminal refusing the empty.
4. Name the reason. Cargo not available, a government hold, no return location, a terminal closure. Tie it to the 545.5 factor it matches.
5. File inside the window through the contact and process the invoice lists, keep the submission, and put the response deadline on the calendar.
6. Tell your customer. If the charge is being passed through, say it is disputed and hold that line item until the dispute closes.

Passing charges to your customer without losing margin

A drayage carrier usually sits between the line or terminal that bills the charge and the customer who caused, or at least owns, the delay. To recover the cost cleanly, each charge needs two numbers: what the supplier billed you and what you bill the customer. It also needs a period with its free days and excluded dates, so that the same days are not billed twice and the customer can check the arithmetic the way you checked the line's. Post it to the load before the customer invoice goes out; a charge found after invoicing turns into a separate bill nobody expects.

Keep the customer's terms in writing before the move: who pays storage if the box is not released, who pays per diem if their dock holds the box, and whether a pre-pull or a dry run is billable. The last free day guide covers the dispatch side of keeping these charges from starting at all.

How TruckerPro records container charges

TruckerPro's Intermodal & Drayage workspace is on the Elite plan and up, switched on in company Settings. Each container charge is recorded on the container as terminal or rail storage, container detention or per diem, chassis rental, yard storage, pre-pull, chassis split or flip, dry run, empty return, waiting time, overweight, reefer or genset, or another service. A charge is fixed, by calendar day or by weekday, with free days and excluded dates, and carries both a customer rate and a supplier cost, so the revenue and the cost are both on record. Overlapping daily charges for the same period are refused.

A draft charge is either posted to the load as an accessorial on the customer invoice, which works only before the load is invoiced, or waived. It can be linked to the supplier's bill in payables, and a dispute with the supplier is tracked with its status (open, submitted or resolved), a dispute deadline and an evidence note. Every change is logged as an event on the container. Terminal status is recorded by your team; TruckerPro does not pull it from terminals or shipping lines. See all features or what a TMS does.