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Container demurrage and per diem calculator
Demurrage is the daily charge for a container left at the terminal or rail ramp past its free days; per diem, or container detention, is the daily charge for keeping the box out past its free days before it comes back empty. Count every calendar day from the first free day to the day it leaves or returns, subtract the free days, and charge each remaining day at its tier's daily rate.
- Thu, Sep 24
- Last free day
- 9
- Days used
- 5
- Charged days
How demurrage and per diem are worked out
Days used = out date − first free day + 1
Last free day = first free day + free days − 1
Charged days = days used − free days (never below zero)
Charge = the charged days in each rate step × that step's daily rate, added up
- Calendar days count, weekends included, unless the tariff excludes weekends or holidays from free time.
- The last free day is free: the first charged day is the day after.
- Tiered rates step up after a set number of charged days; each day bills at the rate of the step it falls in.
Worked example
One import box at the ramp, one out on per diem.
Container EGHU 604412 7, a 40' high cube at the CN Brampton ramp, had 4 free days from Mon, Sep 21, so its last free day was Thu, Sep 24. Still at the ramp on Tue, Sep 29, it has used 9 days: 5 charged at $220.00 CAD a day, $1,100.00 CAD so far. Picked up on Fri, Oct 2, it would owe $1,760.00 CAD.
Container MSCU 482117 3 went out to the customer on Tue, Sep 22 with 5 free days, to Sat, Sep 26. Still out on Tue, Sep 29: 3 days of per diem at $150.00 CAD, $450.00 CAD.
The example box, day by day
| Date | Day | Status | Charge | Running total |
|---|---|---|---|---|
| Mon, Sep 21 | 1 | Free | CA$0.00 | CA$0.00 |
| Tue, Sep 22 | 2 | Free | CA$0.00 | CA$0.00 |
| Wed, Sep 23 | 3 | Free | CA$0.00 | CA$0.00 |
| Thu, Sep 24 | 4 | Free | CA$0.00 | CA$0.00 |
| Fri, Sep 25 | 5 | Charged | CA$220.00 | CA$220.00 |
| Sat, Sep 26 | 6 | Charged | CA$220.00 | CA$440.00 |
| Sun, Sep 27 | 7 | Charged | CA$220.00 | CA$660.00 |
| Mon, Sep 28 | 8 | Charged | CA$220.00 | CA$880.00 |
| Tue, Sep 29 | 9 | Charged | CA$220.00 | CA$1,100.00 |
| Wed, Sep 30 | 10 | Charged | CA$220.00 | CA$1,320.00 |
| Thu, Oct 1 | 11 | Charged | CA$220.00 | CA$1,540.00 |
| Fri, Oct 2 | 12 | Charged | CA$220.00 | CA$1,760.00 |
Free tool
Demurrage and per diem questions
What's the difference between demurrage and per diem?
Demurrage is charged while a loaded container stays at the terminal or ramp past its free time. Per diem, also called container detention, is charged while the container is out, with the trucker or the customer, past its free time until it comes back. One box can run up both.
When does free time start?
Terminal free time usually starts when the container is discharged or available for pickup; per diem free time starts when it's gated out. The carrier's or terminal's tariff says which, so enter the first day that counts.
Do weekends and holidays count?
Usually, because most tariffs count calendar days, but some exclude weekends or holidays from free time. This calculator counts calendar days; check the tariff for exclusions.
How do tiered demurrage rates work?
Many tariffs raise the daily rate after a set number of charged days. For example, at $150.00 a day for the first 4 days and $250.00 a day after that, 6 charged days cost 4 × $150.00 + 2 × $250.00 = $1,100.00.
Is the last free day charged?
No. A container picked up or returned on its last free day owes nothing; the first charged day is the day after.
Roadmark prices demurrage and per diem per container, every day past the last free day.
Every import on one clock, with the pickup drafted before the free time runs out.
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Let Roadmark work it out on every load.
Bring a week of your own loads. We'll show you the detention, weights, classes and free-time charges Roadmark would have worked out from your ELD times, dimensions and terminal dates.
- Worked from your own loads, not a script
- Every figure shown with where it came from
- Runs beside the TMS you have today