Detention vs Demurrage: the Difference

Short answer: Demurrage and detention are two separate delay charges that apply when you do not return cargo or equipment within the free time. Demurrage runs while the loaded container is still inside the port or terminal, so it covers the time you take to clear customs and collect it. Detention runs after the container has left the terminal, until you return the empty container to the shipping line or the designated depot. Both depend on the carrier's tariff and the terms of the bill of lading, so we do not quote fixed amounts or day counts here.

The difference at a glance

| | Demurrage | Detention | |---|---|---| | Where is the container? | Inside the port or terminal | Outside the terminal, in your hands (warehouse, factory, trucker) | | When does it start? | After free time ends following discharge | After free time ends once the container leaves the terminal | | When does it stop? | When the container is collected from the terminal | When the empty container is returned to the drop-off point | | Who is it paid to? | Usually the shipping line (terminal storage is a separate item) | The shipping line | | Common causes | Customs, paperwork or payment delays; no truck arranged | Late unloading, late return of the empty, traffic or warehouse congestion |

The same container can accrue both charges one after the other: first demurrage, then detention once it leaves the terminal. They are separate clocks and do not count the same day twice.

What is free time?

Free time is the number of days you can use the container before charges begin. The carrier states it in its tariff or in your quote, and it can be structured in one of three ways:

• Separate periods: one number of days for demurrage and another for detention.
• Combined free time: a single total that counts days both inside and outside the terminal.
• None or very short: on some routes or special arrangements, free time is minimal.

Free time should be settled at the quote stage. "How many days of free time, and is it combined or separate?" is one of the most important questions to ask when you request a freight quote. Also confirm in writing when the count starts (vessel arrival, discharge, the moment the box lands on the yard) and whether weekends and public holidays are counted.

Why do these charges happen?

1. Documents arrive late: if the bill of lading, invoice or certificate of origin is late, customs clearance cannot begin and demurrage accrues.
2. Release delays: without the original bill of lading or a telex release, the carrier will not hand over the cargo.
3. Customs inspection: a physical check or a request for extra documents extends the stay.
4. No truck available: if the pickup day was not planned, the truck is late.
5. Late unloading: the container reaches the warehouse but the crew or space is not ready, so detention runs.
6. Return depot far away or full: if the drop-off terminal is congested or needs an appointment, the return slips.

Practical steps to avoid the charges

• Get free time written into the quote. The number of days, combined or separate, the start point and the tariff after free time ends should be stated if possible.
• Prepare documents before the vessel arrives. Have the bill of lading, commercial invoice, packing list and customs documents complete ahead of arrival.
• Plan clearance and trucking in advance. Arranging the truck around the vessel's arrival lowers demurrage risk.
• Book the unloading day and the return point early. If an appointment is needed for the empty return, make it up front.
• Track the clocks. Write the discharge date and the last free day in a calendar.
• Tell the carrier early if you will be late. An early message can sometimes open room for an extension or an alternative; it is never guaranteed, but silence is worse.

What to check when you receive an invoice

1. Do the free time start and end dates match the bill of lading and the tariff?
2. Were causes outside your control, such as vessel delay, terminal closure or strikes, counted against you?
3. Are the container number and return date correct?
4. Was the charge calculated using the right tariff tier?

If you find an error, write to the carrier or its agent with supporting documents.

Common mistakes

• Assuming that paid freight means no other charges. Demurrage, detention and storage are usually outside the freight quote, so read the quote carefully.
• Treating combined free time as separate. Using the same days twice breaks your calculation.
• Ignoring weekends and holidays. Some tariffs count them.
• Keeping the container at the warehouse. Delaying the return of the empty after unloading starts the detention clock.

A worked example (hypothetical)

The day counts below are invented to show the logic only; read your real free time from your quote and the carrier's tariff. Say the quote states "7 days combined free time". The container is discharged and, because documents are late, waits 4 days in the terminal; those 4 days are deducted from free time. It leaves the terminal on day 5 and stays 2 days at your warehouse, so the combined allowance reaches 7 days. If you then keep the empty box 3 more days before returning it, detention applies to those days. If the free time were separate (one allowance inside, another outside), the result would be quite different. So "combined or separate" alone can change the cost.

Questions to ask when reading a quote or bill of lading

• How many days of free time, and when does the count start?
• Is free time separate or combined for demurrage and detention?
• Does the daily rate step up after free time ends?
• Where is the return point, and is an appointment needed?
• Are weekends and public holidays counted?
• In which currency, and to whom, are the charges paid?

Once the answers to these six questions are in writing, the chance of a surprise during the shipment drops noticeably.

How Medius helps

When we prepare a quote we try to clarify with you what free time applies and which extra charges are or are not included, so you know before the shipment starts what is covered. Amounts vary by carrier, route and period, so current terms are written into each quote. To get a quote for your route, contact us.