Customs Demurrage Penalty Tracker
First billable penalty day when a container overstays port free time.
These calculators are for informational purposes only and do not constitute legal, financial, or professional advice.
How the Customs Demurrage Penalty Tracker works
The Customs Demurrage Penalty Tracker takes the date a container becomes available at the terminal and the number of free days your carrier grants, and returns the first day demurrage starts billing — the first penalty day after free time runs out. Enter the availability date, the free-day allowance, and whether those days are counted as calendar or working days; the tool counts forward, skipping the holidays of the port country you select.
The clock anchors to availability — typically discharge from the vessel and customs release, summarized by the terminal as a posted Last Free Day — not to the day your trucker or warehouse is ready. That start date governs everything, so confirm it from the terminal before you count. Free time is a carrier grace period, commonly a few days, defined by the carrier's tariff and your service contract rather than by law.
Whether free days run in straight calendar days or only working days changes the answer, sometimes by several days when a long weekend or port holiday falls inside the window. Set the count to match your tariff, and read the result as the first billable day so you can prioritize the pickup before charges — which often escalate by tier — begin.
Worked example
A container posted available on Monday the 1st with five working free days: counting forward and skipping the weekend, the fifth free day is the following Monday, so the first billable demurrage day is Tuesday the 9th. Switch the same five days to calendar-day counting and free time expires on Friday the 5th, making Saturday the 6th the first billable day — same container, same "5," three days apart.
Frequently asked questions
What date does the demurrage clock start from?
From the date the container becomes available for pickup — usually vessel discharge plus customs release, which the terminal publishes as the Last Free Day — not the day you were ready to collect it. Confirm that availability date with the terminal, because every downstream date depends on it.
Do free days count weekends and holidays?
It depends on the carrier's tariff. Some count free time in straight calendar days including weekends; others count only working days, which quietly extends your runway across a long weekend or port holiday. Set the calculator to match your tariff, because the same free-day number can land days apart between the two methods.
Is demurrage the same as detention, and is this advice?
No. Demurrage is for cargo left inside the terminal past free time; detention is a separate clock for keeping the carrier's container out too long before returning it empty. This tool tracks the demurrage start day only. It is general information, not legal or contractual advice — confirm any real charge against your bill of lading, the carrier's tariff, and the terminal.
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