Demurrage vs Detention: The Charges That Catch Importers Out

Two invoices arrive after a delayed shipment. One says demurrage, one says detention, and both are for more money than the delay felt like it was worth. Most importers pay them without ever being clear on what the difference is, which is exactly why the same charges keep recurring.

The distinction is simple once you see it, and it is worth learning, because the two charges have completely different causes and completely different fixes.

Inside the Gate or Outside It

Demurrage is charged while your loaded container is still sitting inside the terminal after your free time has run out. You have not collected it. The terminal wants the space back.

Detention is charged once you have taken the container out of the terminal and kept it too long before returning the empty. You have the carrier's equipment and they want it back in circulation.

That is the whole distinction. Demurrage is dwell time inside the gate. Detention is possession outside it. If you remember nothing else, remember that a container cannot accrue both at the same time, because it cannot be in two places at once.

The Free Time Clock

Both charges begin only after an allowance called free time expires. There is no single national standard for how long that is. Free time varies by carrier, by port and by what your contract negotiated, and commonly falls somewhere in the region of three to seven days for demurrage and around four to seven days for detention.

The date that matters is the Last Free Day. After that, charges accrue per container, per day, and they typically escalate in tiers rather than staying flat. Published tariffs frequently start in the region of $150 to $300 per container per day and step up materially the longer the container sits, so a delay that runs into a second week does not cost twice as much as the first week, it costs considerably more.

Multiply that across a multi container shipment and a five day delay stops being an administrative annoyance.

Why It Is Often Not Your Fault, and Why You Pay Anyway

This is the part importers find hardest to accept. Port congestion, a customs hold, a chassis shortage, a terminal appointment system with no available slots. None of these are things you control, and the charges accrue regardless.

There is recourse. The Federal Maritime Commission has tightened the rules on how demurrage and detention must be billed, including what information an invoice has to contain and who may be billed. An invoice that does not meet those requirements can be challenged. In practice, a meaningful share of charges are reduced or removed when someone actually disputes them with the documentation to back it up, and almost none are reduced when nobody asks.

The Four Things That Actually Prevent Them

Know your Last Free Day before the vessel arrives, not after. It should be a date in your system the moment the booking is confirmed. Most demurrage is incurred by people who found out about the deadline once it had passed.

Have customs clearance ready to file, not started, on arrival. Entry can be prepared in advance. If your broker is waiting on documents when the ship berths, you have already spent part of your free time.

Book the trucking before you need it. Appointment slots at busy terminals are a constraint in their own right. A container that is cleared but has no collection slot still accrues demurrage.

Plan the empty return. Detention is often incurred at the very end, when a container sits at a warehouse over a weekend because nobody arranged the return leg. It is the cheapest of all these to avoid and the most commonly forgotten.

Negotiate the Free Time Instead

If your lane is consistently tight, the durable fix is contractual rather than operational. Additional free time can be negotiated, particularly on regular volume, and it is far cheaper to agree extra days up front than to pay tiered charges on every shipment. Importers rarely ask, which is precisely why it is often available.

Demurrage and detention are not fixed costs of importing. They are a symptom of a timeline that was too tight, and timelines are something you can change.

If these charges are showing up on your shipments regularly, get in touch. We build the clearance and collection timeline backwards from the Last Free Day, which is the only order that reliably keeps containers moving.