Demurrage: what it is, what it costs, and how to get it reversed
Demurrage is a per-container, per-day charge the ocean carrier bills when a full container stays inside the terminal beyond your free time.The clock starts when the box becomes collectable — not when the vessel discharges — and the daily rate escalates in tiers. Free time is filed per carrier and per port of discharge, typically 3–7 calendar days on dry import boxes.
What is demurrage? (Demurrage meaning, in one paragraph)
Demurrage is the penalty you pay for keeping a carrier’s full container inside a port terminal longer than the free days in your tariff or contract. It exists because a container sitting behind the gate is a box the carrier cannot turn around and re-use — the charge is compensation for that lost equipment time. The carrier files the rate with the port (in US trades, in its FMC-published tariff), prices it per container per day, and raises the daily rate the longer the box sits. Demurrage is chargeable to the “merchant” on the bill of lading — usually the consignee on imports — even when the delay was caused by a forwarder, a customs broker, or the terminal itself. That last point is why so many demurrage invoices are disputable.
Demurrage vs detention — which charge is which?
The two charges share one clock — free time — but run on opposite sides of the terminal gate. Demurrage runs while the full container is inside the terminal, from availability to gate-out. Detention (per diem) runs while the carrier’s container is outside the terminal in your possession, from gate-out to empty return. A box stuck behind a closed gate racks up demurrage; a box sitting at your warehouse waiting to be unloaded racks up detention. Some carriers and ports merge both into a single “combined demurrage & detention” free-time pool — the grid below flags those ports.
Pre-clear customs before the vessel arrives — a customs hold burns your free days while the box is not even collectable.
Book the pickup appointment the day the availability notice lands, not when free time is about to expire.
Track the last free day, not the discharge date — the clock starts at availability. Set an alert 48 hours before it expires.
Negotiate free time at contract signature, not at the invoice — 7–10 days on imports is achievable for volume shippers, and your contract overrides the tariff.
Keep the POD, gate logs and availability notices — when the invoice is wrong, the party with the timestamped records wins.
Enter the availability date, your free days and the carrier’s per-diem tiers. The calculator applies weekend and port-holiday rules and returns a line-by-line breakdown you can send to the carrier.
Container timeline
Per-diem tiers
Leave the days field blank on the final tier so it covers every remaining day.
Days 1–5
Days 6–10
Day 11+
Breakdown
Elapsed days
17
Free time expires
2026-08-06
Chargeable days
12
Days excluded
0
Days 1–5 · 5d × $150
$750
Days 6–10 · 5d × $250
$1,250
Day 11+ · 2d × $400
$800
Per container
$2,800
Total exposure$2,800
Think you were overbilled?
Most disputes are won on the clock anchor: carriers bill from discharge, but free time starts at availability. Send us the invoice and we run a blind audit — you pay only on recovery.
Import free time for a 40’ dry container, derived from the carrier’s tariff structure plus the prevailing local rule at each port. Pick a carrier to change the grid.
Figures are tariff-structure derived, not a substitute for your filing. Open a Free-Time Matrix page for the port-specific watch-outs, escalation bands and clock-start mechanics.
When demurrage is disputable
The clock started too early
Carriers routinely start free time at discharge rather than at the availability or release notification. Every day between the two is carrier-side and comes off the invoice.
No appointment or gate was available
If the terminal offered no slot, or the gate was closed, the dwell was not merchant-caused. Under the US FMC rule the charge must serve an incentive purpose — it cannot if collection was impossible.
Customs, carrier or terminal hold
Inspection dwell, missing release, or a hold placed by the line stops the merchant clock in most filings — but it is almost never credited automatically.
Wrong free time or wrong tier
The port-of-discharge filing, your service contract and the equipment type each change the free days. Applying the wrong one is the single most common billing error we recover.
Double billing of the same dwell
Terminal storage or quay rent and carrier demurrage are separate invoices for the same days at several ports. Paying both is a straight overcharge.
Defective invoice (US imports)
FMC rule 46 CFR 541 requires 13 specific elements on a demurrage invoice. A missing element eliminates the obligation to pay the charge.
Already been billed?
Upload the demurrage invoice and we audit it line by line against the filed tariff and the terminal record, then produce a carrier-ready demand pack. No software to install, NDA before you send anything, and you only pay on money recovered.
Demurrage is a charge the ocean carrier bills when a full container stays inside the terminal beyond the free time agreed in the tariff or service contract. It is priced per container per day and is normally tiered, so the daily rate rises the longer the box sits.
How is demurrage calculated?
Count the days from the date the container became available for collection to the date it left the terminal, subtract the contractual free days, then price each remaining day at the tariff tier that covers it and multiply by the number of containers. Some tariffs count free time in working days and exclude weekends and port holidays.
When does the demurrage clock start?
It starts when the container is commercially collectable — the availability or release notification — not on the vessel discharge date. Days between discharge and availability are carrier or terminal side and are not chargeable to the merchant.
How much free time do I get before demurrage starts?
Typically 3 to 7 calendar days on dry import containers, but free time is filed per carrier, per port of discharge and per equipment type. Reefer and special equipment usually get 0 to 3 days. Your service contract overrides the published tariff.
What is the difference between demurrage and detention?
Demurrage runs while the container is inside the terminal. Detention runs while the container is outside the terminal in your possession, between gate-out and the return of the empty. If the box is behind the gate it is demurrage; if it is on the road or at your yard it is detention.
How do you avoid demurrage charges?
Pre-clear customs before the vessel arrives, book the pickup appointment as soon as the availability notice lands, track the last free day rather than the discharge date and set an alert 48 hours before expiry, negotiate extended free time at contract signature, and keep timestamped PODs, gate logs and availability notices so a wrong invoice can be proven wrong.
Can demurrage charges be disputed?
Yes. The strongest grounds are: the clock started before the container was actually available, terminal appointments or gate closures made collection impossible, customs or carrier-side holds caused the dwell, the wrong free time or tariff tier was applied, or — for US imports — the invoice is missing the 13 elements required by FMC rule 46 CFR 541, which eliminates the obligation to pay.