Demurrage and detention
How much is detention (per diem) per day?
The short answer
Freight Benchmarks found that where per diem (detention) bills state the days, the median rate was $172 per container per day, with the middle half between $150 and $195, and the median bill covered 2 days. That is from US import container shipments first invoiced July 2024 to June 2026, of which 3.7% paid per diem.
Cite this figure: Median per diem (detention) rate per container per day
Freight Benchmarks (2026). Median per diem (detention) rate per container per day: $172. Per container per day, on bills that state the days billed; lump-sum bills are left out, across all published ports. Shipments first invoiced July 2024 to June 2026; data version 2026-10-22. https://freightbenchmarks.com/answers/how-much-is-detention-per-day/#fig-per-day-rates-per-diem-rate-median-usd (CC BY 4.0)
Cite this figure: Median days billed on a per diem (detention) bill
Freight Benchmarks (2026). Median days billed on a per diem (detention) bill: 2. Per container per day, on bills that state the days billed; lump-sum bills are left out, across all published ports. Shipments first invoiced July 2024 to June 2026; data version 2026-10-22. https://freightbenchmarks.com/answers/how-much-is-detention-per-day/#fig-per-day-rates-per-diem-days-median-days (CC BY 4.0)
Cite this figure: Median per diem (detention) bill per container
Freight Benchmarks (2026). Median per diem (detention) bill per container: $350. Per container: shipments that carried a single container, so the shipment's bill is that container's bill, across all published ports. Shipments first invoiced July 2024 to June 2026; data version 2026-10-22. https://freightbenchmarks.com/answers/how-much-is-detention-per-day/#fig-per-container-national-per-diem-median-usd (CC BY 4.0)
How per diem is charged
Once a loaded container leaves the terminal, the ocean carrier allows a number of free days to deliver it, unload it and bring the empty back. After that it bills detention, which US carriers usually call per diem, for every day the container stays out, per container, until the empty is returned. The rate comes from the carrier’s tariff or your service contract, and like demurrage it can climb the longer the box is out.
Per diem builds up at the destination end: a slow unload, a warehouse short of dock doors, a drop delivery that sits in the yard, or a terminal that won’t take empties back for that carrier. Weekends and holidays often count.
What a day costs on real invoices
In Freight Benchmarks’ invoice data, 58.7% of per diem bills state the days. On those, the median rate was $172 per container per day, the middle half ran from $150 to $195, and 1 in 10 was over $250. The median bill covered 2 days, and 1 in 10 covered more than 8.
Counted per container on single-container shipments, the median per diem bill was $350. Per shipment across all shipments it was $370, and 3.7% of shipments paid any per diem at all. Rates by port are on the per diem fee page.
Per diem, demurrage and chassis days
Per diem is one of three daily clocks on a container. Demurrage runs while the loaded box is still inside the terminal: see how much demurrage costs per day. The chassis it rides on is billed by the day too: where bills state the days, an extra chassis day ran a median $55, and a trucked container was billed a median 3 chassis days. A late empty return usually runs per diem and chassis days up together.
Check the days on the invoice
Under the Federal Maritime Commission’s billing rule, which covers per diem, a detention invoice from an ocean carrier has to show the free time, the dates the charges cover and the rate, among other details, and one that leaves any of them out doesn’t have to be paid. The steps are in how to dispute a demurrage or detention invoice. This is general information, not legal advice.
What to do
- Plan the unload before the container leaves the port, especially on drop deliveries, so the empty can go back inside its free days.
- Ask whether detention free days are calendar or working days, and whether they are combined with demurrage free time.
- Return empties promptly and keep the gate-in receipt (the terminal’s interchange record) as proof of the return date.
- If a terminal refused your empty or had no return appointments, save the evidence. It is grounds to dispute the days: see how to dispute a demurrage or detention invoice.
Questions
Is per diem the same as detention?
In US container shipping, usually yes. Per diem is the daily detention charge the ocean carrier bills while its container is outside the terminal past the free days, until the empty is returned.
How many days of per diem do importers usually pay?
In Freight Benchmarks' invoice data, the median per diem bill that states the days covered 2 days per container, and 1 in 10 covered more than 8 days.
How often do importers pay per diem?
3.7% of US import container shipments first invoiced July 2024 to June 2026 paid per diem, and when they did, the median bill was $370 per shipment.
Does per diem stop when the container is unloaded?
No. It runs until the empty container is returned to the carrier's designated terminal or depot, so a container unloaded on time but returned late still pays.
Sources
- 46 CFR 541.3: definitions, including demurrage or detention and per diem (eCFR)
- 46 CFR 541.6: what a demurrage or detention invoice must include (eCFR)
- Freight Benchmarks figures: Anonymized line-item forwarder invoices billed to US importers, contributed through the Freight Benchmarks data partner program, in which every partner is a licensed US freight forwarder and customs broker. Aggregates only. See the methodology.
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