# Dwell fee vs demurrage: what is the difference? > Demurrage is the standard charge for a loaded container left on a marine terminal past its free time, set in a carrier's or terminal's tariff and covered by federal billing rules. A dwell fee is not a standard charge: the name has been used for separate fees on long-sitting import boxes, one approved by the Ports of Los Angeles and Long Beach in 2021 and never collected, and one Port Houston charges today on top of demurrage. _Updated Oct 12, 2026._ Demurrage is the everyday charge, and a dwell fee, where one exists, is an extra layer aimed at boxes that have sat far longer. The Federal Maritime Commission's plain definition is that "demurrage accrues when a container exceeds free time on a marine terminal," while detention "is charged for extended use of intermodal equipment." Its rules treat both as charges assessed by ocean carriers, marine terminal operators or ocean transportation intermediaries for the use of terminal space or containers (46 CFR 545.5). A dwell fee appears nowhere in those definitions. ## Demurrage: the contractual charge Demurrage is written into the billing party's tariff or contract, starts when free time runs out, and accrues per container per day. Since May 28, 2024, the FMC's billing rule has set the paperwork. An invoice must go out within 30 calendar days of the last day the charge was incurred, or the billed party is not required to pay it (46 CFR 541.7). It must list the container number, the start and end dates of free time, the container availability date for imports, the specific days charged and the daily rate (541.6), and it must give the billed party at least 30 days to ask for a refund or waiver (541.8). One section of the rule, on which party may be billed, was set aside by the D.C. Circuit in September 2025 and removed effective December 29, 2025. ## The San Pedro Bay dwell fee that was never collected The best-known dwell fee was an emergency measure. On October 25, 2021, at the height of that year's congestion, the Ports of Los Angeles and Long Beach announced a charge to ocean carriers, not cargo owners, for import containers that sat on their terminals too long: nine days or more for boxes leaving by truck, six days or more for boxes leaving by rail. It was $100 per container, rising by $100 per container each day until the box left. Both harbor commissions approved the Container Excess Dwell Fee on October 29, 2021, Los Angeles by a 4-0 vote. In January 2022 Los Angeles moved the rail threshold to nine days, the same as truck. The ports postponed the fee week after week, later in four-week holds, and phased it out on January 24, 2023. It was never activated: the ports said cargo owners cleared the long-dwelling boxes themselves, and aging cargo on the docks fell 92% across the two ports. ## Port Houston's dwell fee, charged today Port Houston runs a dwell fee that is live. Its Tariff No. 15, effective September 1, 2026, charges a Sustained Import Dwell Fee of $48.53 per container per day, starting on the eighth day after free time expires, and says it "will be charged in addition to the demurrage." When Houston announced the fee in December 2022, at $45 a day, the port said payment would be the cargo owner's responsibility. ## A worked example Take one truck-bound import box at Los Angeles in late 2021, had the fee been switched on. On its ninth day on the terminal the carrier would have owed $100, on its tenth $200 and on its eleventh $300: $600 for three days, separate from any demurrage. At Houston today, a box ten days into the dwell fee owes 10 x $48.53 = $485.30 in dwell fees, and demurrage for the same days on top. ## Where the nine-day line sits today [Chart: Share of POLA import boxes dwelling 9+ days](https://the-dwell.com/boxdwell/los-angeles-import-containers) ([data](https://the-dwell.com/boxdwell/los-angeles-import-containers.md) — chart image: https://the-dwell.com/charts/boxdwell/los-angeles-import-containers/chart.png) The nine-day line from 2021 is the same one the Port of Los Angeles still reports in its daily dwell count, charted above. The latest reading: 18.8% of import boxes at 9+ days (10,637 boxes of 56,437 boxes). For rail-bound boxes, both San Pedro Bay ports publish the same nine-day split: Long Beach 16,901 import boxes waiting for rail (10.2% at 9+ days), Los Angeles 20,220 (33.3% at 9+ days), on the [port rail container dwell](/boxdwell/rail-dwell-la-long-beach) page. These are counts of boxes, not fees. The Dwell explains how these charges work. It does not tell you whether a charge on an invoice is valid or how to contest one. For the free-time mechanics, see [demurrage, detention and free time](/guides/demurrage-detention-and-free-time); for the day count, the [last free day calculator](/tools/last-free-day-calculator), and for where one box's stay falls against the nine-day line, the [container dwell time calculator](/tools/container-dwell-time-calculator); and for the dates on a single booking, [container milestone tracking](/guides/container-milestone-tracking). ## Related data + guides - [Demurrage, detention and free time](https://the-dwell.com/guides/demurrage-detention-and-free-time) - [Last free day calculator](https://the-dwell.com/tools/last-free-day-calculator) - [Los Angeles import-container dwell](https://the-dwell.com/boxdwell/los-angeles-import-containers) - [Port rail container dwell: Los Angeles vs Long Beach](https://the-dwell.com/boxdwell/rail-dwell-la-long-beach) - [Container dwell time calculator](https://the-dwell.com/tools/container-dwell-time-calculator) ## Common questions ### What is the difference between a dwell fee and demurrage? Demurrage is the standard tariff charge for a container left on a marine terminal past its free time. A dwell fee is not a standard charge; where one exists, such as Port Houston's Sustained Import Dwell Fee, it is a separate daily fee on boxes that have sat well past free time, charged on top of demurrage. ### Did Los Angeles and Long Beach ever collect the container dwell fee? No. The ports announced it in October 2021, postponed it repeatedly and phased it out on January 24, 2023 without ever activating it. ### Who pays a dwell fee? It depends on the fee. The 2021 San Pedro Bay fee was aimed at ocean carriers. Port Houston said its dwell fee is the cargo owner's responsibility. ### How long does a carrier have to bill demurrage? Under the FMC's billing rule, 30 calendar days from the last day the charge was incurred. If the invoice is issued later, the billed party is not required to pay it. --- Canonical URL: https://the-dwell.com/guides/dwell-fee-vs-demurrage