What it means
A carrier lends a container for a shipment and needs it back for another load, and ports also need terminal space, so free time gives the customer a defined window to move cargo without certain time-based charges. Demurrage generally concerns a carrier container held inside the terminal beyond allowance, while detention concerns time outside the terminal before return, and some carriers combine them into one clock.
A fictional importer with five days of terminal free time collects the container on day four, but whether later detention applies depends on a separate or combined allowance. "Free" does not mean all shipping costs disappear, because freight, handling, customs and other charges may still be due and it only describes specified time-based amounts under the contract.
A fictional shipment clears customs within the free window, yet the buyer still pays ocean freight and terminal handling. Start and end events are load-bearing, since a carrier may count from vessel discharge, gate-out or another named event and the tariff can count calendar or working days under local rules.
A fictional company assumes the clock begins when it receives notice, but its contract starts at discharge instead, so the logistics team corrects the pickup plan. Import and export movements differ, because an export container can spend time outside the terminal before gate-in and inside before vessel loading, and each segment may have its own allowance.
A fictional exporter collects an empty container on Monday, loads it at its warehouse and returns it to the port, and the return time affects detention under its carrier's terms. The amount of free time can vary by country, port, equipment type and negotiated contract, and refrigerated or special containers may have different conditions, so confirm the actual booking.
A fictional importer handling both standard and refrigerated boxes does not copy the standard allowance to the refrigerated shipment and checks the rate schedule separately. Storage charged by a terminal can be distinct from carrier demurrage, so multiple clocks may run at once, and a fictional importer facing a port storage invoice and carrier demurrage reconciles both under their respective tariffs because one paid bill does not automatically clear the other.
Plan customs documents, delivery appointments and trucking early, since delays at one step can consume the allowance, and monitor the container's actual milestones. A fictional shipment lacks a required permit, so the forwarder flags the issue before arrival and seeks a remedy, because waiting until the last free day makes charges more likely.
Calculate exposure with the exact start date, free days and daily tariff schedule, since rates may rise in bands after several days and a simple flat-rate estimate can be wrong, as when a fictional container three chargeable days late is charged different rates for days one and three and finance sums each band, not one guessed average. Extensions may be negotiable before arrival or under specific circumstances, but a customs hold does not automatically stop every carrier clock in every country, so obtain written confirmation, as a fictional importer facing an inspection does when it asks the carrier whether the allowance can change and keeps evidence.
Returning an empty container correctly matters, because a late or wrong-depot return can continue detention, so keep gate receipts and equipment interchange records; a fictional trucker who drops an empty box at an unauthorised depot leaves the clock running until the carrier accepts it. Free time is a planning window, not a universal number of days, so a manager should assign responsibility for each milestone, with the forwarder tracking release, the trucking firm confirming pickup and the receiving site preparing unloading, to prevent a window being lost through handoff delays.
In practice
Real-world examples.
Example
An importer collects a container within terminal free time.
Example
Detention starts after an agreed outside-terminal window.
Example
A combined clock covers both terminal and inland periods.
Formula
Calculation
Illustrative chargeable days = elapsed tariff days - applicable free days, subject to exact clock rules and rate bands.
Worked example: a fictional container has 5 free days and is returned on day 9, so chargeable days = 9 - 5 = 4. If the tariff charges $75 a day for chargeable days 1 and 2 and $120 a day for chargeable days 3 and 4, the exposure is 2 x $75 + 2 x $120 = $150 + $240 = $390. A flat estimate of 4 x $75 = $300 would understate the bill by $90.Case study
Seen in the real world.
In this fictional case, Harbor Imports assumes it has seven days after a notification email. The carrier's clock actually starts at vessel discharge. The forwarder verifies discharge, gate-out and empty-return times. It calculates each tariff period and improves future pickup scheduling.
Watch out
Common mistakes.
- Treating free time as a waiver of all freight costs.
- Confusing terminal demurrage with outside detention.
- Assuming a customs hold always pauses the clock.
Questions
People also ask.
How many days are free?
It depends on the carrier, port and agreed terms.
Can days be combined?
Some contracts use a combined demurrage-and-detention period.
When does the clock stop?
Check the applicable gate or return event in the tariff.
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