Demurrage and detention are the two charges that never show up in your freight quote and then arrive as an invoice with a comma in it. They accrue by the day, they compound across every container in a shipment, and they're most often triggered by delays that feel like they weren't your fault. Most importers can't cleanly explain the difference between the two, don't track the clock that starts them, and pay bills they had every right to dispute. All three of those are fixable.

Demurrage vs. Detention — the Difference That Matters

They sound interchangeable. They're not, and billing them correctly depends on the distinction.

  • Demurrage is charged when your container sits at the terminal, past its free time, waiting to be picked up. The box hasn't left the port yet.
  • Detention is charged when you've taken the carrier's container out of the terminal — to your warehouse — and held it past the free time to unload and return the empty. The box is out in the field.

A memory aid: demurrage is the container stuck at the dock; detention is the container you're detaining out at your building. (You'll also hear detention called "per diem.") And note that a terminal's own storage charge can stack on top of a carrier's demurrage for the same container — two meters, same box.

Free Time and the Last Free Day

Carriers grant a limited window of "free time" — often just a handful of days — before the meter starts. The deadline is the Last Free Day (LFD), and it's the single most important date attached to any container. After the LFD, charges run daily, and they usually escalate in tiers: the longer the box sits, the higher the per-day rate climbs. Free time varies by carrier, port, and your freight contract, which is exactly why you have to know the number for each shipment rather than assume it.

Why They Blindside Importers

Three reasons D&D catches people out: it isn't in the freight quote, so it's invisible until it bills; it's frequently triggered by things that feel outside your control; and it multiplies — a per-day charge across ten containers held five days is a very different number than it looks like per box. By the time the invoice lands, the damage is done.

What Actually Triggers Them

  • A customs hold or exam — the goods are flagged and can't be released.
  • Missing or late paperwork — no telex release or original bill of lading, an ISF problem, duty not paid, clearance not filed.
  • No chassis available to move the container.
  • Your warehouse can't take the delivery in the free-time window — no appointment, no labor, no space.
  • Port congestion — not your doing, but frequently still your bill.
  • Returning empties late — the classic detention trigger.

How to Stay Ahead of Them

Almost all D&D is prevented upstream, before the ship arrives:

  • File early. ISF on time, customs entry pre-filed, duty ready, broker instructed — so nothing holds the release.
  • Arrange the release. Confirm the telex release or original BL is in hand before the vessel lands.
  • Know the free time and track the LFD on every container — and the earliest return date for the empties.
  • Pre-book drayage, chassis, and a warehouse appointment before the LFD, not after.
  • Return empties promptly and track the detention clock the same way you track demurrage.
  • Negotiate more free time into your freight contract — volume buys days.

You Can Fight an Improper Bill

Here's what most importers don't know: since OSRA 2022 and the FMC's Demurrage and Detention Billing Rule (effective May 28, 2024), these invoices have to meet strict requirements — and if they don't, you may owe nothing.

  • A compliant invoice must include specific information: the bill of lading number, why you're the proper party to bill, the allowed free time in days with its start and end dates, the container availability date, the earliest return date, and the exact dates demurrage or detention are charged.
  • Only the party who contracted for the transportation or the consignee can be billed — one of them, not both.
  • You have 30 days to file a request for a waiver, refund, or fee mitigation, and the biller has 30 days to respond.
  • The big one: if the invoice omits any of the required information, the obligation to pay that charge is eliminated.

So don't pay a D&D invoice on receipt. Audit it against those requirements first — a surprising number don't comply, and the non-compliant ones are challengeable.

The Real Fix Is Visibility

Every dollar of demurrage and detention is, at bottom, a symptom of not knowing where a container is and when its clock runs out. When you're tracking each box's availability date, last free day, and empty-return deadline — and the documents and appointments are staged ahead of them — most D&D simply never happens. The fee is what you pay for the visibility you didn't have.

This is general guidance, not legal advice. Demurrage and detention rules and your specific free-time terms vary by carrier and contract — confirm current FMC requirements and your dispute rights with your customs broker, forwarder, or trade counsel.

What's the worst D&D bill you've eaten — and when you look back, was it a paperwork delay, a chassis or warehouse gap, or an invoice you could actually have disputed? We'd like to hear what it cost and why.