DEM, DET, Storage and Free Time: How They Differ and How to Avoid Container Charges

On many import shipments, the biggest cost overrun is not ocean freight or trucking, but a few abbreviations on the shipping line's invoice: DEM, DET, Storage. They are charged per day, rise in tiers, and keep running on Sundays and public holidays. This article separates the three charges, explains when free time starts counting, walks through a concrete example and sums up what businesses can do to avoid paying them.

1 How DEM, DET and Storage Differ

All three are charges for “keeping a container too long”, but they differ in where the container is and who charges. A short definition of each is already in the ocean freight surcharge table; here the three are placed side by side to show where the boundaries lie:

A common confusion: DEM and Storage run in parallel over the same period the container sits at the port, but they are two invoices from two different parties. The shipping line charges for holding its equipment; the port charges for occupying yard space. At Cat Lai, the port's charge appears as a lift-on surcharge based on storage days — reference figures are in the article on how container trucking rates are calculated.

For export cargo the direction is reversed: DET runs from picking up the empty at the depot until the laden container is gated into the port, and DEM runs from gate-in until the vessel departs. Picking up the empty too early or gating in too long before the cut-off can both trigger charges.

2 How Free Time Is Counted

Free time is the number of days the shipping line grants free of charge before DEM and DET start. Three things to know before relying on a figure like “7 days free”:

• It counts calendar days — including Saturdays, Sundays and public holidays. If the vessel berths on the Friday before the Tet holiday, most of the free time passes before anyone can process the paperwork.
• The discharge day usually counts as day one, not the day the arrival notice is received.
• Free time can be separate or combined. Separate: for example 5 days DEM and 5 days DET, each clock running independently. Combined: for example 10 days covering the whole period from discharge to empty return. The two lead to different strategies — see the example in section 3.

The number of free days is not fixed by port but by shipping line, route, container type and contract. Reefers and special equipment usually get fewer free days and higher daily rates than dry containers. For the exact figure, ask the shipping line or forwarder at the time of booking and have it written into the booking confirmation.

3 Worked Example of Overdue Charges

A 40-foot import container arrives at Cat Lai and is discharged on 01/11. The rates below are assumptions to illustrate the calculation, not any shipping line's tariff — in practice rates rise in tiers and differ between carriers.

Two conclusions from the example:

• With separate free time, pulling the container out of the port early stops DEM (usually the more expensive clock) and stops port storage — but the DET clock starts. It only pays off if the cargo is then unloaded and the empty returned quickly.
• With combined free time, gating out early or late does not change what you pay the shipping line; the only thing that reduces the charge is the empty return date. Pulling out early only helps avoid port storage.

In other words, every solution comes down to one question: when can the cargo be unloaded from the container. If the container has arrived but cannot be collected yet, see the common causes and how to resolve them.

4 Why Containers Often Exceed Free Time

Most of the DEM and DET cases CARIMEX sees come down to five causes:

• Slow customs clearance — missing documents, an uncertain HS code, a declaration routed to the yellow or red channel, or waiting for specialised inspection results. This is the number one cause, and also the one that can be prevented before the vessel berths — see how to prepare under CARIMEX's customs declaration service.
• Late delivery order — local charges not yet paid, no original bill of lading, or the seller has not yet released the cargo by telex.
• The warehouse cannot receive in time — many containers arriving at once, a full warehouse or not enough labour to unload.
• No truck available on the right day — peak season, year end, the run-up to Tet.
• Late or wrong-depot empty return — the designated depot is far away or full, or the container is rejected for being dirty or damaged and needs cleaning or repair.

5 8 Steps to Avoid Paying Container Charges

• Request free time that matches your real unloading schedule, at the time of booking. When importing on FOB terms the buyer chooses the shipping line and can negotiate; on CIF the seller chooses the carrier — so ask the seller to secure extra free time at the destination port in the sales contract.
• Prepare customs documents before the vessel berths. The law allows the import declaration to be filed before the goods arrive at the border gate; the HS code and specialised permits should be settled when placing the order, not once the container is already at the port.
• Watch for the arrival notice and get the delivery order early. Pay local charges and sort out the bill of lading before the vessel berths, rather than starting only after it arrives.
• Book container trucking in advance. Give the transport company the schedule as soon as the arrival date is known so a truck is ready the moment clearance is granted — CARIMEX provides import container trucking from Cat Lai and Cai Mep to industrial parks in Dong Nai.
• Schedule unloading with the warehouse. When several containers arrive in the same week, sequence the unloading and prioritise those closest to the end of free time.
• If the warehouse cannot receive yet, unload at an off-port yard and return the empty. A cleared container can be moved to the Nhon Trach container yard, unloaded and stored temporarily at the yard, and the empty returned early — stopping both port storage and the DET clock, instead of leaving the container at the port waiting for warehouse space.
• Return the empty to the right depot, clean, and keep the equipment interchange receipt. The receipt records the return date — the basis for checking the DET invoice and getting the container deposit back.
• Check the invoice before paying. Verify three dates: discharge, gate-out and empty return; and whether the free days applied match the booking confirmation.

6 What to Do Once You Are Already Overdue

If a container has exceeded or is about to exceed free time, the order of priority is:

• Request a free time extension immediately — through the forwarder or directly with the shipping line, before it expires. Customers with steady volumes are often considered; asking after charges have accrued is much harder.
• Work out which clock is more expensive and deal with it first: with separate free time and DEM costing more than DET, prioritise getting the container out of the port as soon as it clears.
• Clear the documentation bottleneck — for a held declaration, focus on supplying exactly the documents customs has requested instead of waiting.
• Return the empty as soon as unloading is done, even if the cargo has not yet gone into the main warehouse.

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