Free tool
Detention and demurrage calculator
Enter the free time and the rate from your contract. The charge is the time beyond free time, rounded as the contract says, times the rate.
Truck detention (hours)
A truck and driver held at a shipper or receiver beyond the free time. Enter the two clock times, the free time and the rate from your contract.
Results appear here as you fill in the fields.
Container demurrage (days)
A container left inside the port or terminal beyond its free days. The clock normally starts when the container is available for pickup; confirm the start event in the terminal's own tariff.
Results appear here as you fill in the fields.
Per diem (days)
A container, and sometimes its chassis, kept outside the terminal beyond its free days. The clock normally starts at gate-out; confirm the start event in your carrier's tariff.
Results appear here as you fill in the fields.
Total across the charges you filled in
Fill in at least one card above to see a total.
How the calculation works
- Write down the start event and the end event, with times and time zone.
- Subtract the free period the contract grants, in hours or in days.
- Round the way the contract says: by hour, by fraction of a day, with a stated minimum.
- Multiply by the contracted rate, per hour or per day.
- Keep the evidence: gate times, the appointment record, signed pickup and drop paperwork.
The same steps, with a worked example and the points where disputes start, are in detention calculation: how to bill it. If this calculator and that guide ever disagree, the guide is the one to trust and the calculator has a bug.
What this calculator does not know
- Your contract, your carrier's tariff or a terminal's rules. You supply the free time, the rate and the counting rules.
- Holidays, or a daylight saving change between the start and the end.
- Whether a charge is valid. It does the arithmetic on the numbers you enter; a dispute turns on the contract wording and the evidence.
Frequently asked questions
What is the difference between detention, demurrage and per diem?
Detention is a truck and driver held at a shipper or receiver beyond the free time. Demurrage is a container left inside the port or terminal beyond its free days. Per diem is a container, and sometimes its chassis, kept outside the terminal beyond its free days. All three have the same shape: a free window, then a rate per hour or per day on the time beyond it. They differ in which event starts the clock and who owes whom.
How is detention calculated?
Chargeable time is the time on site minus the free time, rounded the way the contract says, multiplied by the rate. For example, 08:00 to 13:30 is 5.5 hours; with two hours free that leaves 3.5 chargeable hours, and at an example rate of $75 an hour the charge is $262.50.
Does the calculator know my carrier's or terminal's rules?
No. It holds no tariff, rate or free-time rule. You enter the free time, the rate and the counting rules from your own contract or from the terminal's or carrier's published tariff, and it does the arithmetic. Port and terminal rules change, so check the terminal's own page for the current wording.
Does it store or send what I enter?
No. The numbers you type stay in your browser tab. Nothing is saved, sent to a server or put in the page address, and it is gone when you close the tab.
Does it handle holidays or daylight saving time?
Not automatically. Days can be counted as every calendar day or with Saturdays and Sundays skipped. If your tariff also excludes holidays, adjust the free days or the dates to match it. Clock times are treated as times at one location, so a daylight saving change between the start and the end is not modelled.
Related
See it running on your kind of data.
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