Northeast Freight Time one clock, four readings

Demurrage Is Not Detention

The two words are used interchangeably in conversation and are not interchangeable on an invoice. They describe different things, in different places, with different free-time conventions, different rate structures and — on the ocean side — different regulatory treatment. For a software-oriented reference on recorded work time and accountability, workforce analytics software.

An invoice using the wrong one is worth examining closely, because it usually means the charge was generated rather than checked. For broader freight and commercial context, see FMCSA.

Reviewed August 9, 2026.

The distinction

Demurrage is storage. A loaded container sitting at the port terminal beyond its free time. The cargo has not left the facility.

Detention is equipment held. A container, chassis or truck kept outside the terminal beyond its allowance. The equipment has left and not come back.

The simplest test: demurrage is about where the box is; detention is about how long you have kept it.

On the road side there is no demurrage. A dry van at a warehouse dock is detention, full stop, and an invoice calling that demurrage has applied the wrong term and possibly the wrong rate schedule.

The numbers, roughly

Demurrage free time commonly runs three to seven calendar days after discharge, depending on the carrier's tariff and the specific terminal, then accrues daily per container.

Detention free time on the ocean side is measured in days for containers and chassis. On the road it is the two-hour convention — not regulation, not derived from anything, and negotiable.

Road detention rates run roughly $50 to $100 per hour after the free window in 2025–2026 reporting, with specialised equipment to about $125.

Treat all of these as ballpark and check your own tariff and contract. Rate structures here change more often than definitions do.

Why the confusion is expensive

Different parties are responsible. Demurrage generally sits with whoever controls cargo release; detention with whoever holds the equipment. Those can be different companies, and a misapplied term sends the invoice to the wrong one.

Different free-time clocks. Days against hours, and different start events. A charge computed on the wrong clock is wrong by a large multiple, not a rounding.

Different dispute paths. On the ocean side, demurrage and detention are both covered by the FMC's billing rule, which requires the invoice to show which container, what period and how the amount was calculated. On the road there is no equivalent, and the FMC's requirements are a persuasive standard rather than an obligation.

And it signals process quality. An invoice that misuses the term was generated by a system nobody checks. If the term is wrong, the timestamps deserve the same scrutiny.

What to check on a container charge

Which word the invoice uses, and whether it matches the physical situation.

Whether the container was actually available for pickup during the period charged. Terminal availability records and appointment confirmations are what support a merits dispute here, and they need to be kept at the time rather than reconstructed later.

Whether free time was computed from discharge or from availability. These differ during congestion, and the difference is the entire charge on a bad week.

And whether the invoice contains the required elements. Under the FMC rule, a missing element removes the obligation to pay as issued — that is a stronger position than arguing the merits, and it costs nothing to check first.

What to check on a truck charge

That it is called detention.

That the free-time allowance and rate match the rate confirmation, and that the confirmation defines the start event rather than saying "after 2 hours."

That timestamps come from somewhere other than the claiming party alone. A single-source claim is the commonest reason detention invoices go unpaid.

The one-line version to keep

Box sitting at the terminal: demurrage. Equipment you are holding: detention. Truck at a dock: detention, and there is no demurrage on the road.

That sentence prevents most of the errors in this category, on both sides of the invoice.

The short version