Fees and the clock
What does import dwell date mean on a container tracking screen?
There is no standard definition of an import dwell date: it is not an event in the industry's container tracking standard, and no US regulator defines it. Where a tracking screen or terminal portal shows one, it most likely marks where that system starts counting the box's days on the terminal, usually discharge from the ship. It is a counting date, not a billing one: demurrage runs from the free-time dates, which a US invoice must state along with the container availability date.
Updated Oct 12, 2026
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An import dwell date is not a standard milestone, so start with what it is not. The Digital Container Shipping Association's track-and-trace standard, the industry's shared vocabulary for container events, lists discharge (DISC), available for pick-up (AVPU) and gate-out (GTOT) as separate container events, each tagged actual, planned or estimated. It has no dwell event. Neither the Federal Maritime Commission's demurrage rules nor its 2015 staff report on demurrage define a dwell date either. So when a screen shows one, read it against the events around it.
What the field most likely counts from
Dwell is time on the terminal. UNCTAD, the UN trade and development body, defines container dwell time as the time containers spend in port "after being discharged from a ship until it leaves the port for delivery to clients." Terminal systems pick a start event for that count, and they do not all pick the same one: ECT's terminal portal in Rotterdam lets a user count dwell from the discharge time or from the time the container arrived at the terminal. An import dwell date is most likely that start point for the box in question. Check which event it matches before you count anything from it.
Why it is not your free-time date
The dates that decide charges are the free-time dates. The FMC's 2015 staff report on demurrage says import free time typically runs from discharge until the container leaves the terminal, ending at an appointed time on the last free day, so a dwell count and a free-time count can start on the same day. They do not have to: a box can be released to a trucker only once it has customs clearance, a release from the ocean carrier and delivery instructions at the terminal, and each tariff sets its own start rule. Since May 28, 2024, the FMC's billing rule has required every demurrage or detention invoice to show the start and end dates of free time and, for imports, the container availability date (46 CFR 541.6). Those are the dates to check a bill against. A dwell date is not on that list.
A worked example
The gap between a dwell count and a free-time count is easy to see on one box. A container discharged on September 14 but not released for pickup until September 16, and still on the terminal on September 23, has dwelt nine days counted from discharge, but it has been available for only seven. Whether its free time started on the 14th or the 16th depends on the tariff, and the invoice has to say which.
Port Houston's tariff shows how a dwell clock can sit on top of free time. Under its Tariff No. 15, effective September 1, 2026, loaded import containers get seven days of free time, beginning with the first 6:00 a.m. after the terminal receives the box. Demurrage follows. Starting on the eighth day after free time expires, the port adds a Sustained Import Dwell Fee of $48.53 per container per day, charged in addition to demurrage. Ten days of that fee come to $485.30 before any demurrage. The box's dwell count, its free-time dates and its fee dates are three different clocks.
The aggregate picture at Los Angeles
- 9+ day share
The Port of Los Angeles publishes the aggregate version of this count every business day: how many import boxes are on its terminals and how long they have sat, in 0-4, 5-8 and 9-plus day buckets. The latest report reads 18.8% of import boxes at 9+ days (10,637 boxes of 56,437 boxes). It cannot date any single box, but a rising 9-plus share means more boxes are carrying a long dwell count.
The Dwell does not track individual containers and this is not billing advice. For every timestamp on a booking and which system publishes it, see container milestone tracking; for how free time and demurrage work, see demurrage, detention and free time; and for the day count, the last free day calculator, or the container dwell time calculator for a box's whole stay. The three meanings of dwell at a port are covered in what is dwell time in shipping.
Try it
Dwell days are the calendar days between the two dates: a box discharged on the 1st and picked up on the 8th has 7. The bucket uses the Port of Los Angeles report's own bounds, 0-4, 5-8 and 9 or more days. Free days are counted the same way as on the last free day calculator, starting the day after free time begins, and the days after the last free day are calendar days up to the pickup date. The weekday option skips Saturday and Sunday only, not holidays. The Los Angeles shares are from the port's report of Oct 21, 2026. This is a day count on the dates you enter, not fee, demurrage or billing advice.
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Now look at the live data
Common questions
What does import dwell date mean?
It is not a standard term. Where a tracking screen shows it, it most likely marks where that system starts counting the import box's days on the terminal, usually discharge from the ship. It is a counting date, not a billing one: the free-time dates and the last free day are what set demurrage.
Is the import dwell date the same as the discharge date?
Often the dwell count starts at discharge, which is how UNCTAD defines container dwell, but systems differ: ECT's terminal portal in Rotterdam can count from discharge or from arrival at the terminal. Compare the dwell date with the discharge date on the same screen.
Does demurrage start from the import dwell date?
Not necessarily. Demurrage starts when free time ends, and free time follows the tariff's own start rule, which may or may not fall on the day the dwell count starts. A US demurrage invoice must state the start and end dates of free time and, for imports, the container availability date.
Is there a fee tied to import dwell?
At Port Houston, yes: its tariff adds a Sustained Import Dwell Fee of $48.53 a day from the eighth day after free time expires, on top of demurrage. The Ports of Los Angeles and Long Beach approved a dwell fee in 2021 but never collected it; see the guide on dwell fees vs demurrage.