Detention and Demurrage Invoices: How to Check and Dispute Them

To check a detention or demurrage invoice, compare it against the Federal Maritime Commission’s required contents, confirm it arrived within 30 days of the last charge date, and recalculate the free time yourself. If required details are missing, the rule says you do not have to pay. You can also dispute within at least 30 days.

Container charges are where a cheap freight quote turns expensive. A box held at the terminal for a customs exam, or a slow return from your warehouse, can add hundreds of dollars a day. Many importers pay these invoices without reading them. That is a mistake, because the billing rules now favor the party that does read them.

This guide is for importers moving full containers from Asia to US ports. It covers what the rules require on an invoice, what a 2025 court ruling changed, and a practical way to check and dispute charges.

Detention vs. Demurrage: What You Are Being Charged For

Demurrage and detention both charge you for time, but in different places. Demurrage applies while a full container sits in the terminal after its free time ends. Detention applies when the container is outside the terminal, usually at your warehouse, past its free time.

Free time is the number of days included in your freight rate before charges start. It often ranges from a few days to a week, depending on the port and contract. After that, daily rates often climb the longer the box sits.

When I priced freight, the free-time line was the one most buyers skipped. It decides more of the final bill than the base ocean rate on a delayed shipment.

What a Valid Demurrage Invoice Must Include

The Federal Maritime Commission (FMC) set out the minimum invoice contents in its final rule on demurrage and detention billing. The rule was published in February 2024 under the Ocean Shipping Reform Act of 2022 and took full effect in May 2024. The full text of the FMC billing rule groups the required details into five areas.

Use this list as your checklist when an invoice arrives.

The consequence for gaps is spelled out in the rule. Failure to include any required information eliminates the billed party’s obligation to pay that charge. In practice, many invoices still miss the container availability date or the certification statements.

How Long Does a Carrier Have to Send the Invoice?

A carrier or terminal must issue the invoice within 30 calendar days of the date the charge was last incurred. If it misses that window, you are not required to pay. An NVOCC passing on a carrier’s charge gets 30 days from the date it received its own invoice.

The rule also protects your time to respond. The billing party must give you at least 30 calendar days from the invoice date to request a reduction, refund or waiver. It must then try to resolve your request within 30 days, unless you both agree to more time.

Track these dates in a simple spreadsheet. For each container, log the last free day, the date charges stopped and the date the invoice arrived. In our experience, late invoices are more common than most importers assume, and timing alone is often enough to challenge one.

What the 2025 Court Ruling Changed

In September 2025, the US Court of Appeals for the D.C. Circuit struck down one section of the FMC rule. In World Shipping Council v. FMC, the court vacated the part that limited who carriers could bill. According to a client alert from law firm Holland & Knight, the court found the FMC’s reasoning on motor carriers inconsistent.

The practical effect is narrow but real. Until the FMC writes a new rule, there is no federal limit on which party a carrier or terminal sends the bill to. Truckers and brokers may see more of these invoices, and they will pass them back to you.

The rest of the rule still stands. The required invoice contents, the 30-day issuing deadline and the dispute window all remain in force. The invoice must also still explain why the billed party is liable.

Step by Step: Disputing a Detention or Demurrage Charge

A dispute works best when it is short, specific and in writing. Here is the order I would follow.

The FMC offers several routes. Its guide to services available to shippers describes charge complaints as a quicker, less formal way to challenge a bill. Its dispute resolution office can also help settle a disagreement before it becomes a formal case.

What to Put in a Written Dispute

A good dispute fits on one page. The person reading it handles dozens a week, so make the problem easy to see and easy to fix.

Include these points, in this order.

Keep the tone factual. Quote the rule section where it helps, but do not lecture. A clear request for a corrected invoice often gets a faster yes than a demand to cancel the whole charge.

Send the dispute through the channel listed on the invoice, and keep the sent copy. If the billing party never answers within 30 days, that silence becomes useful evidence if you escalate to the FMC.

Preventing Demurrage Caused by Customs Holds

The cheapest charge to dispute is the one you never incur. Many demurrage bills start with a customs or partner-agency hold, and those holds usually trace back to paperwork.

Start with the Importer Security Filing, often called ISF or 10+2. According to U.S. Customs and Border Protection, failing to comply can lead to penalties, more inspections and cargo delays. A late or wrong ISF is a common reason a box sits at the terminal.

Classification errors cause holds too. A code that flags the wrong agency, or misses one that should be flagged, can stop an entry. Our guide on how to find your HTS code and when to ask CBP for a binding ruling covers how to get that right.

Regulated consumer products add another layer this year. Missing certificate data can now hold an entry, as our explainer on the CPSC eFiling test data you need from your factory sets out. Each day of delay adds to the demurrage clock.

A Fair Note on Carrier Charges

Not every detention or demurrage charge is unfair. Carriers use these charges to keep containers moving, and a box left at a warehouse for three weeks costs the carrier real money. Disputing valid charges wastes your time and can strain a relationship you need.

The aim is accuracy, not avoiding every bill. Pay the charges that are correct and on time. Challenge the ones that are late, incomplete or caused by the carrier.

Turning Invoice Checks Into a Habit

FMC rules give importers real leverage over detention and demurrage invoices. A valid invoice must show specific details, arrive within 30 days and allow at least 30 days to dispute. The 2025 court ruling changed who can be billed, but not those protections.

Your next step is to pull the last three container invoices you paid. Check each one against the list above. If any are missing details or arrived late, you have a template for every future dispute.