A Docket shipment flagged critical: demurrage in 7 days, EPR registration missing and a fumigation stamp query, above the invoice, route, free-time and CHA details. — A container against its clock — free time ends 14 Jul, two documents unresolved.

Combined demurrage and detention: one clock, not two

Combined demurrage and detention is a carrier tariff that allows one block of free time across both charges instead of one each. Maersk's published Singapore import tariff gives five free days, discharge to empty gate-in, so the gate-out that splits the two clocks elsewhere divides nothing. Running the detention sum separately and adding it counts days twice.

Combined demurrage and detention: A carrier tariff that treats demurrage and detention as a single charge on a single clock, running from vessel discharge to the return of the empty container, against one allowance of free days rather than one allowance for each. The gate-out event does not split the count.

One clock, Singapore import, Maersk's published tariff Five free days, then three rate bands. The gate-out, which separates demurrage from detention on most tariffs, is not a boundary here.

Most of this site counts two clocks. The terminal or the carrier charges demurrage while the container sits inside the gate; the carrier charges detention on its own equipment once the box leaves. Two documents, two allowances, two rates, and the gate-out between them.

A combined tariff does not work that way, and one of the largest lines on the Singapore import trade publishes one.

Combined Demurrage and Detention starts from the day discharge (included) and ends with gate-in empty at the depot (included).

That is Maersk’s import tariff for Singapore, effective 5 July 2024 and “applicable for all import cargoes to Singapore both IAS and Non-IAS trades”. One sentence, and it removes the boundary every separate-clock calculation is built on.

What it changes about the arithmetic

Two published tariffs, one port, two shapes Both documents cover an import container at Singapore. They disagree about how many clocks there are.

The usual method for a demurrage and detention calculation is to run the sum twice: demurrage from discharge to gate-out against the demurrage allowance, detention from gate-out to empty return against the detention allowance, then add the two.

Against a combined tariff that method is wrong twice over. It prices two allowances where the tariff grants one, and it counts the gate-out day on both sides of the boundary. On five free days covering the whole span, a desk that budgets four free days for the terminal half and six for the return half has given itself ten days it does not have.

The correct sum is shorter. Count from the day of discharge to the day of empty gate-in, both included. Take the free days off the front. Price the rest band by band.

The bands, and why one multiplication is not enough

The 40-foot dry bands, Singapore import, SGD per day The rate steps up twice. Pricing twelve chargeable days at the first band understates the bill. Source: Maersk, Singapore local information — Import, Demurrage and detention: "Import combined DnD Tariff, effective 5th July 2024", applicable to all import cargoes to Singapore. "Combined Demurrage and Detention starts from the day discharge (included) and ends with gate-in empty at the depot (included)." Per container per day in SGD, days 1-5 free on all equipment, then 85/110/140 on a 40ft dry across days 6-10, 11-20 and 21+, and 45/75/100 on a 20ft dry. The tariff is "subject to storage and other surcharges upon the terminal tariff".

The published table has four rows and the rate steps up twice, so a chargeable period that crosses a band cannot be priced by multiplying the day count by the headline rate.

Work a 40-foot dry container discharged on day 1 and returned empty on day 14. Days 1 to 5 are free. Days 6 to 10 are five days at SGD 85, which is SGD 425. Days 11 to 14 are four days at SGD 110, which is SGD 440. The combined charge is SGD 865. Pricing all nine chargeable days at SGD 85 would have reported SGD 765, about 12% light and on the wrong side.

Reefers and special equipment, which the tariff defines to include open top and flat rack, run at roughly double the dry rates in every band. The tariff adds that IMO and non-operating-reefer cargo is charged as its size and type, so a hazardous consignment is not separately tariffed here the way it is at Jebel Ali.

Two carriers, one port, two shapes

The reason to know the word at all is that the other model is published for the same port. Ocean Network Express’s Singapore agency tariff allows four working days of import demurrage and six of detention, and says where the join is: detention is “computed from the date/time container(s) exit PSA Gateway(s) to the date/time the empty container(s) return to Empty Depot”. Two allowances, split at the gate, and counted in days that exclude Saturdays, Sundays and the public holidays the Ministry of Manpower declares.

Maersk’s table is headed “Days” and states no exclusion for weekends or holidays at all.

So on one lane, into one port, two lines publish a different number of clocks, a different number of free days, and days that are not the same unit. A desk working free time off a remembered figure is right for one carrier and wrong for the other, and nothing on the bill says which rule was applied.

There is one more practical catch, and it is the reason this belongs to the document pack rather than to the invoice.

Maersk’s own instructions for its demurrage and detention calculator say the feature “is only accessible to import parties in shipment (Consignee and First Notify Party)”, with the appointed haulier able to reach it as Release to Party once a delivery order has been submitted. The combined last free date, the one number the whole charge turns on, is therefore visible to the parties named on the bill of lading and to nobody else.

That makes the notify party field a scheduling field. A box named to a forwarder who is not watching the clock has a last free day that the desk paying the charge cannot look up.

And the terminal still bills separately

The combined figure covers the carrier’s two charges. It does not cover the port’s. The tariff’s own note reads:

The tariff is subject to storage and other surcharges upon the terminal tariff.

So a late clearance at Singapore produces a carrier charge an importer can look up and a terminal storage charge they cannot, because PSA publishes no storage tariff of the kind DP World publishes for Jebel Ali. Two custodians, one of them silent.

Which puts the controllable part back where it always is. Document packs routinely run about eight days late against free time, and on a combined tariff those eight days are spent out of a single allowance covering the whole span from discharge to empty return. Working the pack backwards from one last free day is easier than working it backwards from two — and it is the only part of this a desk controls, which is what demurrage and detention software that counts back from the last free day is for.

Questions traders ask

How do I do a detention charges calculation when the tariff is combined?

Once, not twice. A combined tariff gives you one allowance and one running total, so you count from the event the tariff names to the event it names — on Maersk's published Singapore import tariff, from the discharge day to the empty gate-in day, both included — then price those days against the tariff's bands. The separate-clocks method, where you run demurrage from discharge to gate-out and detention from gate-out to empty return and add the two figures, charges the gate-out day twice and prices two allowances the tariff never granted.

What is combined demurrage and detention?

A single charge covering both the box sitting in the terminal and the box sitting with you. The usual arrangement is two charges: the terminal or the carrier bills demurrage while the container is inside the gate, and the carrier bills detention on its own equipment after the container leaves. A combined tariff collapses that into one clock with one free period. Maersk's Singapore import tariff states it in one line: "Combined Demurrage and Detention starts from the day discharge (included) and ends with gate-in empty at the depot (included)."

Which is it on my shipment — combined or separate?

Whichever your carrier's tariff for that port and direction says, and the two models sit side by side on the same lane. At Singapore, Ocean Network Express's published agency tariff allows four working days of import demurrage and six of detention, computed on either side of the exit from the PSA gateway. Maersk's published import tariff for the same port allows five days across both, discharge to empty return. Neither is the market default, so the only answer that binds a given box is the document that covers it.

Does a combined tariff mean I pay less?

It means you pay on one allowance instead of two, which usually means less tolerance rather than more. Five days covering discharge-to-empty-return is a shorter leash than four working days to the gate plus six working days back to the depot, because the second arrangement does not start spending the return allowance until the box is actually out. Where a combined tariff helps is the arithmetic: there is one last free day to work backwards from rather than two.

Is the terminal's storage charge inside the combined figure?

No, and the tariff says so. Maersk's Singapore table carries the note that "The tariff is subject to storage and other surcharges upon the terminal tariff", so the terminal's charge for the ground the box occupies sits on top of the combined carrier charge. At Singapore that second bill is the harder one to anticipate, because PSA publishes no terminal storage tariff the way DP World publishes one for Jebel Ali.

Where do I find the combined last free day?

On Maersk's Singapore lane, behind a login and tied to who is named on the bill. The carrier's own instructions say the demurrage and detention calculator "is only accessible to import parties in shipment (Consignee and First Notify Party)", and that once a delivery order is submitted the appointed haulier as Release to Party can reach it too. So the date that decides the charge is available to the party named on the bill of lading and not to anybody else on the desk, which makes the notify-party field a scheduling field as well as a contact one.

What rates does the Singapore combined tariff charge?

Four bands, per container per day, in Singapore dollars, on the import tariff effective 5 July 2024. Days 1 to 5 are free on every equipment type. A 20-foot dry container is then 45 for days 6 to 10, 75 for days 11 to 20 and 100 from day 21. A 40-foot, 40-foot high-cube or 45-foot dry container is 85, 110 and 140 on the same bands. Reefers and special equipment run roughly double: 80, 130 and 160 at 20 feet, and 140, 240 and 300 at 40 feet.

Related terms

Detention — The daily charge a carrier levies for keeping its container outside the terminal beyond the agreed free period, running from gate-out until the empty is returned to the depot the carrier nominates.
Demurrage — The charge a carrier or terminal levies when a container remains inside the port past its allotted free time, accruing daily per container until the box is collected.
Free time — The grace period allowed before demurrage or detention begins to accrue, counted from discharge in plain calendar days at most terminals and in working days at some, and set by the carrier's tariff or by the importer's service contract.
Per diem — The daily charge for the use of a carrier's equipment beyond free time, and chiefly the US term for container detention. Under 46 CFR 541.3 a per-diem charge for a shipping container is a demurrage or detention charge; the same definition excludes charges for other equipment, such as a chassis.
Detention invoice — The invoice a shipping line or an NVOCC issues for the days its container remained outside the line's control after leaving the terminal, stating the bill of lading and container references, the free-time period, the rate per tier and the days charged.
Empty container return — The acceptance of a carrier's empty container back at the depot or terminal the carrier nominates, recorded on an interchange receipt. It is the event that ends the importer's detention liability, and the date it happened is not a required field on the detention invoice.
Carrier tariff — A common carrier's published schedule of its rates, charges, classifications, rules, regulations and practices, kept open for public inspection. It is where free time, demurrage and detention terms are stated, and it is a different thing from a customs tariff, which is a schedule of duty rates.
Working day — In a port or terminal tariff, a day that counts against free time only if the terminal works it. Where free time is allowed in working days, Saturdays, Sundays and named holidays drop out of the count. Where it is allowed in plain days they do not, and the tariff states which in one line.
Terminal storage charge — The charge a marine terminal operator levies for an import container occupying terminal ground beyond its free dwell time, set out in the terminal's published scale of rates and identical for every importer at that terminal, as distinct from the carrier's demurrage.