Laytime is the period of time the charterer is allowed, under the charter party, to load or discharge the cargo without paying the owner anything extra. When it runs out, the ship is on demurrage and the charterer pays the agreed daily rate until the work is finished.
That is the whole idea. Everything else — arrived ships, notices of readiness, weather working days, SHEX and SHINC — exists to answer two questions: when does the clock start, and what makes it stop.
How laytime is fixed
A charter fixes laytime one of two ways.
As a period. "Five weather working days for loading." The allowance is stated directly.
As a rate of work. "8,000 MT per weather working day of 24 consecutive hours." The allowance depends on the cargo actually shipped, so it is not known until the bill of lading quantity is known. Divide the quantity by the rate:
The rate version is the more common in dry bulk, and it is the reason the bill of lading matters to a laytime claim: change the quantity and you change the allowance.
When laytime starts
Three things have to be true before a notice of readiness starts anything.
The ship must be an arrived ship, and what that means depends on the charter. Under a berth charter she arrives when she is at the berth — so congestion is the owner's risk. Under a port charter she arrives when she is within the port and at the charterer's immediate and effective disposition, and waiting time can count. This single distinction decides who pays for a crowded port, which is why clauses like WIBON, WIPON, WIFPON and WCCON exist at all.
She must be ready in fact — holds clean and fit for that cargo, gear working, the ship legally free to work.
The notice must be tendered properly — to the right party, within the hours the charter allows, in the form it allows.
Miss one of the three and nothing has started, whatever the statement of facts says in the margin.
Then comes turn time, the grace period between a valid notice and the start of laytime — twelve hours, twenty-four hours, "on the next working day", whatever was fixed. Two things people get wrong: turn time is not automatic, so no clause means no turn time; and nothing runs from an invalid notice, not turn time and not laytime.
What stops the clock
Once laytime is running, the charter decides what counts.
| Term | What it means |
|---|---|
| SHINC | Sundays and holidays included — everything counts |
| SHEX | Sundays and holidays excepted |
| SHEX EIU | Excepted even if used — the day is excluded whether or not the ship worked |
| SHEX UU | Excepted unless used — but if she worked, the time worked counts |
A weather working day is a working day on which the weather would have permitted work on that cargo — whether or not any work was planned. So at a grain berth the question is not "were we loading?" but "could grain have been worked in that weather?" If rain would have stopped the loading, the period is excluded even if the ship was idle for a reason of her own. And if the weather was fine, a day the shipper chose not to work still counts.
Many charters exclude only the part of the day the weather actually interfered with, not the whole day — which is why the rain entries in the statement of facts, to the minute, are worth more than any argument about them later.
When laytime runs out
Once the allowance is used up the ship is on demurrage, and the rule that follows moves more money than any other in a laytime statement:
The exceptions that protected the charterer while laytime was running generally stop protecting him the moment it runs out. Demurrage runs continuously — day and night, weekends, holidays — until the ship completes. The exceptions to that are an interruption caused by the owner's own fault, or a clause that says in terms that it applies to demurrage as well. Those need express words; general exception clauses are read narrowly against the party relying on them.
If the ship finishes early, many charters pay despatch, usually at half the demurrage rate, for the time saved.
A worked example
Illustrative figures, arithmetic shown in full.
| Cargo | 30,000 MT |
| Rate | 10,000 MT per weather working day of 24 consecutive hours, SHEX |
| Demurrage | USD 18,000 per day |
| NOR tendered and accepted | Monday 08:00 |
| Turn time | 12 hours |
| Completion | Friday 14:00 |
| Rain, excepted | 6 hours in total |
Allowed: 30,000 ÷ 10,000 = 3.00 days = 72 hours
Laytime commences: Monday 08:00 + 12 hours turn time = Monday 20:00
Time elapsed: Monday 20:00 → Friday 14:00 = 3 days 18 hours = 90 hours
Less excepted: 90 − 6 hours rain = 84 hours counted
On demurrage: 84 − 72 = 12 hours
Demurrage due: 12 ÷ 24 × 18,000 = USD 9,000
Move the notice by one hour and every line after it moves too. That is why the start of a statement is worth more attention than the end of it.
The same calculation built as a spreadsheet, with the formulas written out and the five places a spreadsheet gets it wrong, is in laytime calculation in Excel.
Laytime is not laycan
They are confused constantly and they are different things. Laycan is the window within which the ship must arrive and tender her notice — the layday she can first do so, and the cancelling date after which the charterer may walk away. Laytime is how long the charterer then has to work the cargo. Laycan is about the ship turning up; laytime is about what happens once she has.
The documents that decide it
In the order they usually settle the argument: the recap, because that is the deal. The charter party and its riders, because that is the wording. The sale contract, where the claim sits on CIF or FOB terms rather than on the charter — on a GAFTA or FOSFA form, or on the parties' own, which has its own laytime wording and does not have to match the charter at all. The notice of readiness. The statement of facts, signed. The bills of lading, for the quantity the rate is applied to. And the letters of protest, because they are what you have when the statement of facts is wrong.
Common questions
Is laytime the same as demurrage?
No. Laytime is the free time allowed. Demurrage is what the charterer pays once that free time is used up.
Does laytime include Sundays?
It depends on the charter. Under SHINC it does. Under SHEX it does not — but once the ship is on demurrage, the exception usually stops applying.
Who calculates laytime?
In practice operations, chartering or claims, and the broker is often asked to check it. Both sides normally produce their own statement, and they rarely agree at first.
What does an invalid notice of readiness do to the calculation?
Nothing runs from it — not turn time, not laytime. Whether a defective notice can be cured, or has to be re-tendered, is argued on the wording of the charter and the facts of the port call, and the two sides often take different views. That is a judgement for the person running the claim. It is also why a laytime statement should show which notice it counted from, so the assumption is visible rather than buried.
A laytime statement example with exactly that argument in it, priced from both notices, shows what the difference comes to: on that voyage, USD 13,039.93.
Put your own voyage through it
Laytimetech is a drag-and-drop laytime calculator and voyage account console: drop in the charter party, sale contract, notices of readiness and statements of facts and get your laytime statement, line by line, with the clause behind every line. The calculator itself is free — no account, no card. Reading your own documents, the clean exports and the voyage register are what the paid plans add.
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