Demurrage & detention

Demurrage accrues while the container is still inside the marine terminal after free time expires. Detention accrues once the box has left the terminal and the equipment is out on your account, and it runs until the empty is returned to the nominated location. Different clocks, frequently different billing parties, and one shipment can take both in the same week. Chassis per diem is a third charge, billed by the chassis pool rather than the carrier, and it is not covered by any of the rules below.

Free time is shorter than it sounds

Free time comes from a tariff or a service contract, not from statute. Four or five calendar days after discharge is common on the East Coast. Calendar days include the weekend and the holiday on which the gate was shut. Rates are tiered, so the per-day charge steps up after the first band and a week costs far more than seven times a day. And if your free time is measured from the vessel's discharge rather than from the moment your specific container was actually available, two of those days can be gone before anyone could have collected it.

The FMC billing rule is a real defence

The Ocean Shipping Reform Act of 2022 gave the Federal Maritime Commission authority over how these charges are billed. The rule at 46 CFR part 541 has been in force since May 2024, and it does three useful things.

• It fixes who bills, and who gets billed. The invoice comes from the vessel-operating carrier, the NVOCC or the marine terminal operator, and it goes to a single party: the one that contracted for the transportation or the storage. The same charge cannot be billed twice to two different parties, and an invoice arriving from a company you have no contract with is worth challenging on that ground alone.
• It fixes what the invoice must contain. Among other elements: the container number, the date the container was made available, the port of discharge, the allowed free time in days, the last free day, the start and end of the billing period, the rate, the total due, the specific tariff or contract provision relied on, and a digital contact for disputes. The omissions are not cosmetic. A billing party that leaves required information out is not entitled to collect the charge.
• It fixes the clock in both directions. The invoice has to issue within 30 calendar days of the date the charge stopped accruing. The billed party then has at least 30 days to request mitigation, refund or waiver, and the billing party has to resolve that request inside a defined period rather than letting it age. Silence is a failure, not a strategy.

Charges that should never have accrued

The FMC's interpretive rule at 46 CFR 545.5 asks whether a charge served the purpose it exists for, which is to move cargo out and get equipment back. A charge that could not have changed anyone's behaviour is difficult to defend. Days when the terminal was closed. Days when no appointment could be obtained. Days when the container was under a CBP hold, an FDA detention or an intensive examination and could not lawfully be released to anyone.

These are arguments, not automatic outcomes, and they are far stronger with timestamps. Keep the refused appointment screens, the terminal advisories, the hold notice and the release message. A dispute won on documents takes one email. The same dispute argued from memory takes six weeks and usually loses.

If the carrier will not drop it

Beyond the billing party's own mitigation process, the FMC accepts charge complaints against common carriers, with a small claims track handled by a settlement officer for lower-value disputes. It is not quick. It is real, and carriers negotiate differently with a party that plainly knows the procedure exists.

What a broker actually prevents

Most of the demurrage that reaches our desk did not start at the terminal. It started with a filing.

• Entry transmitted before arrival. The entry goes to CBP in advance so release status is in hand at discharge. Under 19 CFR 141.68 entry is not deemed made until the goods arrive within the port limits, but nothing requires the paperwork to wait for the ship.
• ISF filed on time. 19 CFR 149.2 sets the timing: 24 hours before lading for containerised cargo, and no later than 24 hours before arrival for break bulk that is exempt from the advance manifest rule. A late or mismatched ISF earns a hold on a container that was otherwise clean.
• PGA data with the entry, not after it. FDA, USDA, EPA and DOT message sets belong in the same transmission. A missing prior notice number is a two-day hold that began as a two-minute omission.
• Exam planning rather than exam surprise. If a shipment is likely to be examined, the delivery order, the CES arrangements and the trucker should be lined up before the notice arrives. The exam itself is rarely the expensive part. The week of scrambling afterwards is.
• Somebody watching the box. Terminal availability, last free day and empty return location all change without anyone calling you. That is something to track daily, not something to remember.

Free time is not really the subject. A container that clears on discharge never enters the demurrage conversation at all, and that is the outcome we are filing for.

If a charge has already landed and you want a second read on the invoice before you pay it, send it over: contact.