What is the difference between demurrage and detention?

Demurrage is charged while a full container stays inside the terminal after free time; detention is charged while the container is outside the terminal — from pickup until it is returned empty.

How long does a carrier have to bill demurrage in the US?

Thirty calendar days from the date the charge was last incurred. If the invoice is issued later, the billed party is not required to pay it.

Can I dispute a demurrage charge?

Yes. In the US the billed party has at least 30 calendar days from the invoice to request a waiver or refund, the billing party must try to resolve it within 30 days, and the carrier bears the burden of showing the charge is reasonable.

Term

Demurrage

Demurrage is the charge a shipping line or terminal makes when a full container stays in the terminal past its free time — from discharge off the ship until pickup. It exists to keep containers moving. In the US, a demurrage invoice must state the free time and be issued within 30 days, or it need not be paid.

Also called container demurrage, demurrage charges, demurrage and detention, D&DUpdated 12 October 2026

Demurrage and detention

	Demurrage	Detention
Where the container is	Inside the terminal, full	Outside the terminal
Clock starts	When it is discharged from the vessel or train	When it is picked up full
Clock stops	When it is gated out	When it is returned empty to the port or a depot

These are Maersk's definitions. Free time — the days a carrier gives before charging — "differs between ports and carriers". The word is older than the container: the Federal Highway Administration's glossary still gives its rail and shipping sense, a charge for holding a railcar or ship beyond its loading or unloading time.

The US rules

Demurrage and detention cover any charge for using terminal space or containers, including per diem. The Federal Maritime Commission asks whether they work as incentives to keep freight moving, and whether free time is tied to the cargo actually being available to collect.
The shipping line carries the burden of showing a charge is reasonable (Ocean Shipping Reform Act of 2022).
The invoice must show the free time allowed in days, its start date and its end date, among other details; leaving required information off removes the obligation to pay.
It must be issued within 30 calendar days of the date the charge was last incurred, or the billed party need not pay it.
The billed party gets at least 30 calendar days from the invoice to ask for a waiver or refund, and the billing party must try to resolve it within 30 days.

The 2024 rule's section naming who may be billed was set aside by a court and removed in December 2025; the rest of the rule still applies.

Worked example

Suppose free time runs from 2 to 5 March, the line charges USD 175 a day after it, and the container is gated out on 9 March. Hapag-Lloyd's US guide counts calendar days, with holidays left out of free time but charged once free time ends.

Demurrage days = 6, 7, 8, 9 March = 4 × USD 175 = USD 700 · Invoice due by 9 March + 30 days = 8 April

An invoice that arrives after 8 April, or does not state the free time's start and end, need not be paid under the US rule.

The mistake people make

Paying without checking the free time. The invoice has to say when free time started and ended; compare those dates with when the container was actually available — a customs hold or a closed terminal can mean the clock should not have been running.

FAQ

Demurrage: common questions

What is the difference between demurrage and detention?: Demurrage is charged while a full container stays inside the terminal after free time; detention is charged while the container is outside the terminal — from pickup until it is returned empty.
How long does a carrier have to bill demurrage in the US?: Thirty calendar days from the date the charge was last incurred. If the invoice is issued later, the billed party is not required to pay it.
Can I dispute a demurrage charge?: Yes. In the US the billed party has at least 30 calendar days from the invoice to request a waiver or refund, the billing party must try to resolve it within 30 days, and the carrier bears the burden of showing the charge is reasonable.