What is demurrage?
Demurrage is what the shipping line charges when a full container stays at the port terminal longer than the free time it allows after the container is discharged from the vessel. The clock stops when the container is collected.
Free tool for UK importers
Demurrage & detention
cost calculator
See what a slow collection or a late empty return could cost, day by day. Enter your free time and your carrier's daily rates; the estimate updates as you type.
Estimated charges
Estimated charges
Estimated total £630 for 2 containers, £315 per container.
£630for 2 containers · £315 per container
- Demurrage per container
- £255
- 3 charged days
- Detention per container
- £60
- 1 charged day
Every extra day costs
- £170for each extra day at the port before collection. (2 × £85)
- £120for each extra day before the empty is returned. (2 × £60)
Day by day
At the port discharge → collection · 10 days, 7 free
Out with you collection → empty return · 8 days, 7 free
| Charge | Days | Per container |
|---|---|---|
| DemurrageCharged days 1–3 | 3 × £85 | £255 |
| DetentionCharged day 1 | 1 × £60 | £60 |
| × 2 containers | £630 |
Show every day
| Day | Where | Status | All containers |
|---|---|---|---|
| 1 | At port | Free | £0 |
| 2 | At port | Free | £0 |
| 3 | At port | Free | £0 |
| 4 | At port | Free | £0 |
| 5 | At port | Free | £0 |
| 6 | At port | Free | £0 |
| 7 | At port | Free | £0 |
| 8 | At port | Demurrage, band 1 | £170 |
| 9 | At port | Demurrage, band 1 | £170 |
| 10 | At port | Demurrage, band 1 | £170 |
| 11 | Out | Free | £0 |
| 12 | Out | Free | £0 |
| 13 | Out | Free | £0 |
| 14 | Out | Free | £0 |
| 15 | Out | Free | £0 |
| 16 | Out | Free | £0 |
| 17 | Out | Free | £0 |
| 18 | Out | Detention, band 1 | £120 |
An estimate for planning only. Your carrier's tariff and contract decide how days are counted (some include the day of discharge), the rate bands and the currency. Terminal storage or port charges, VAT and any other fees are not included.
Portside warns you before free time runs out.
Every container gets a demurrage and detention countdown from its real dates, turning amber a few days out and red once charges start, so collection and empty returns get booked in time.
Plain English
Demurrage vs detention, explained
Both are daily charges from the shipping line for holding on to its container beyond the free time. The difference is where the container is while the clock runs.
- DischargeDemurrage clock: container at the port
- CollectionDetention clock: container out with you
- Empty returnedBoth clocks stopped
What is detention?
Detention is what the shipping line charges when you keep its container outside the terminal longer than the free time allowed, from collection until the empty container is returned to the depot the line tells you to use.
What is combined demurrage and detention?
Some lines merge the two into one free-time allowance and one daily rate that runs from discharge to empty return. Your contract or the line's published tariff says which applies to you, and how many free days you have.
Why does free time run out?
Usually because something holds the container up: a customs hold or examination, documents that are missing or late (such as the bill of lading, commercial invoice or customs entry), charges that must be paid before release, no haulage or terminal booking slot, or a warehouse that cannot unload in time and so returns the empty late.
Are terminal storage charges included?
No. Some terminals charge their own storage once their free period ends, separately from the shipping line's demurrage. This calculator covers the line's demurrage and detention only, and it is an estimate: your tariff decides how days are counted and which rates apply.
Four ways to protect your free time
Know your free time before you book
Check the free days and daily rates in your contract or the line's tariff for your port. If you regularly need longer, ask about extra free time when you agree rates.
Have documents ready before arrival
Work with your customs broker so the customs entry, invoice and packing list are ready before the vessel arrives, and settle freight charges early so release is not held up.
Book haulage as soon as the ETA firms up
Collection slots can be tight at busy terminals. Keep an eye on ETA changes: an early arrival starts the free-time clock sooner.
Plan the empty return, not just the delivery
Confirm the return depot (it is not always the port) and unload promptly, because detention runs until the empty is back.