Machined in China Lead Times: Doing the Arithmetic Across an Ocean

Buying machined parts from China means planning on a calendar that runs in two currencies. At the factory end, time is measured in working days, punctuated by weekends and the country's own holidays, and a week is whatever the Chinese calendar says it is. At your end, time is measured in transit days across a border, with freight cutoffs, customs clearances and port weekends of their own. A delivery date is the arithmetic that joins these two clocks, and most of the surprises in China sourcing come from plans that treated them as one. This guide walks that arithmetic: how to count working days on the real calendar, how to add the freight leg honestly, and where to place the margins so a date survives the ocean.

Why can the same part take different times from China in different weeks?

The same part, the same factory and the same quantity can produce very different calendar spans depending on the week the order is placed, because both clocks move. In one week the factory has open working days ahead and the parts move into an air shipment that clears customs quickly; in another the order lands just before a holiday shutdown, misses the weekly sea-freight cutoff, and arrives into a port weekend on the far side. The machining content did not change; the calendar around it did. A buyer who treats lead time as a property of the part is surprised by this; one who treats it as a property of the calendar is not.

The practical consequence is that a quoted duration should always carry the dates it assumes — the week the material arrives, the week the parts ship, the mode of freight and the expected arrival window. When those dates are attached, the duration is testable and the calendar is explicit. When a quote offers only "three weeks," it is hiding which calendar it was counted on, and the count will change the moment real dates attach to it.

How do I convert a factory working-day estimate into calendar days?

Factories estimate in working days, and buyers need calendar days, and the conversion is where accuracy lives. The correct method is to take the estimated working days and count them forward across the actual calendar the order will cross, skipping the weekends and the factory holidays that fall in that span, and then to continue past the ship date into the freight leg. Counting on the real calendar is the only way the arithmetic holds, because a five-working-day estimate can span seven calendar days in an ordinary fortnight or two weeks when a holiday interrupts it.

The second half of the conversion is the receiving side. After the freight leg the parts clear customs, move to your receiving dock and pass your own inspection before they are usable, and each of those steps is calendar time that the factory cannot see. A plan that ends at the factory's ship date has left out a third of the journey. The accurate conversion adds the transit, the customs margin and the receiving margin to the working-day count, and it does the whole sum before committing to the calendar date your own production needs.

Which freight mode should my lead-time plan assume?

The freight mode is a scheduling decision before it is a cost decision, because each mode carries its own rhythm. Air freight moves small high-value orders in days, but it runs on flight cutoffs and can be delayed by weather and space pressure in peak seasons. Sea freight moves volume in weeks, but it runs on sailing schedules, port cutoffs and consolidation cycles that are less forgiving than any factory estimate. Door-to-door courier service suits small parcels and handles customs at both ends, but its price per kilo is high and its transit still varies with the destination country's clearance speed.

A plan that leaves the mode vague is a plan that cannot be dated, because "shipping" could mean a week or a month depending on how the shipment actually goes. The discipline is to name the mode in the plan, book it at the right moment in the schedule, and know its cutoff rhythm — the day of the week the factory must have the parts at the forwarder, the day the sailing departs, the day the courier pickup happens. Each cutoff is a date the factory can work back from, and a factory that knows the freight cutoff is a factory that schedules the machining against a real deadline rather than a vague one.

Freight space is itself seasonal, and the season belongs in the arithmetic. Around the pre-holiday peaks and the year-end rush, air cargo space tightens and rates climb, sea containers fill earlier, and a booking that would have moved in days can wait a week for space. A plan that assumes off-peak availability at a peak moment inherits the peak's delays whether it priced them or not. The buyer's move is to ask the forwarder what the space situation looks like for the planned shipping week and to place the booking when the machining schedule is set, so the freight leg is reserved rather than hoped for. The ocean and the sky have their own calendars, and they fill up like any other capacity.

How do Chinese holidays actually stretch a schedule?

The Chinese factory calendar is not the Western one, and the difference is concentrated in two periods. The Spring Festival holiday, which moves between January and February each year, closes factories for more than a week and stretches the weeks around it: buyers ship ahead of the shutdown to protect their schedules, so the weeks before it carry a queue, and the factory re-starts slowly after it because staff return and materials re-stock over several days. The National Day holiday in early October has a shorter but similar effect. A factory working through those weeks is not fully loaded the way it is the rest of the year.

The planning move is to confirm the holiday dates against the actual calendar for the year in question before placing the order, because the dates move annually and assumptions from last year are wrong this year. Then place the schedule on either side of the holidays rather than through them: a part that must arrive by a deadline should ship before the shutdown, and a part that ships after it should be planned for the re-start, not for the holiday week itself. Buyers who treat Chinese holidays as calendar facts, the way they treat their own, are the ones whose China schedules do not mysteriously gain weeks in January and February.

There is also the receiving-side calendar to check before the holiday arithmetic is done. If the parts land at your port or your courier depot during your own holiday week, or during a week when your receiving team is short-staffed, the transit margin quietly grows on your side of the ocean. The two calendars meet at the delivery point, and a date that is safe on the factory side can still be late on your side if the arrival week collides with your own closures. The full arithmetic therefore reads both calendars before it commits: the factory working days out of the Chinese holiday, the freight transit out of the shipping week, and the receiving days out of your own calendar, all counted before a single date is promised to your production line.

Where does the factory's responsibility end in the schedule?

The line between the factory clock and the logistics clock is drawn by the Incoterm, and it decides who owns each day of the journey. Under an ex-works or free-on-board term, the factory's responsibility ends at its door or at the port, and everything after — the forwarder, the freight, the customs at both ends — sits on the buyer's calendar. Under a delivered-at-place term, the factory's schedule absorbs the freight leg and its promise extends to your door. Two buyers can quote the same part from the same factory and receive it on different dates because they chose different terms, and the difference is scope, not speed.

Reading a China quote therefore requires reading the term. When a factory quotes a ship date, ask what the term is and what happens after that point; when it quotes a delivered date, ask what the freight mode and the transit assumption are. The comparison that matters is the one that lands the same part at the same dock under the same terms, and a buyer who compares ship dates without comparing terms is comparing two different products. The term is the contract's map of who owns each leg, and the schedule should be drawn on that map.

What should the handover documents carry to keep the schedule moving?

Customs delays are the most common unplanned addition to an import schedule, and most of them trace to documents. A commercial invoice that does not match the packing list, a value declared in a way the destination questions, or a certificate missing from the package stops the shipment while corrections travel back and forth. Every one of those stops is calendar time added after the parts have already left the factory, and every one is preventable by agreeing the document set at the order stage rather than discovering it at the border.

The handover package for an import order should be defined in the purchase order: the commercial invoice in the format your customs broker expects, the packing list with weights and dimensions that match the crate, the material certificate if the goods require one, and any destination-specific paperwork agreed in advance. The factory prepares these once, to your format, when the parts ship, and the shipment clears because the documents match the goods. The buyers whose imports clear fastest are the ones whose paperwork was specified before the parts existed, not after they were in transit.

How much time should I add between the factory's date and my hard need?

The margin that protects a China schedule belongs between the estimated arrival and the date you truly cannot move, and its size should reflect the variation of the longest leg. If the factory leg is the reliable part and the freight is air, the margin can be a few days; if the freight is sea, or the shipment lands near a holiday, or the destination port has known congestion, the margin should cover a week or more. The margin is not a sign that the plan is weak; it is the price of the ocean, and it is paid in calendar days whether it is planned or discovered.

Where not to put the margin matters just as much. A margin placed inside the factory's working-day estimate invites the factory to consume it, because a promise padded on the inside is a promise that slips to its padding. The honest structure is a factory date that is tight but real, a freight estimate with the mode named, and the margin held between the arrival estimate and the hard need, where only the buyer can spend it. The FAQs on this site cover the working rhythm and holiday planning in more detail, and the home page shows the factory's process flow from order to export. A China schedule built on the real calendar, with the freight mode named and the margin placed at the far end, is a schedule that survives contact with the ocean, and the buyer who counts both calendars is the buyer whose parts arrive when the plan said they would.

Frequently Asked Questions

Why can the same part take different times from China in different weeks?

Because the factory calendar and the logistics calendar both move. The factory works through its own holidays, the freight leg depends on cutoff days, and customs or port weekends add days a borderless calendar never shows. The same work content can span very different calendar lengths depending on where it lands in both cycles.

How do I convert a factory working-day estimate into calendar days?

Count the working days on the actual calendar the order will cross, skipping weekends and factory holidays in that span, then add the transit days of the freight mode and a receiving margin. Converting at the end on the real calendar is accurate; converting at the start with a fixed days-per-week assumption is where errors begin.

Which freight mode should my lead-time plan assume?

Air moves in days for prototypes and critical parts; sea moves in weeks for volume; door-to-door courier suits small parcels between them. Each mode has its own cutoff rhythm, and the plan should name one mode explicitly rather than a vague shipping that could be either.

How do Chinese holidays actually stretch a schedule?

Spring Festival closes factories for over a week and stretches the weeks around it, as buyers ship ahead and the factory re-starts slowly. The October National Day week has a smaller effect. Confirm the dates against the year's calendar and plan on either side of the holidays, not through them.

Where does the factory's responsibility end in the schedule?

At the Incoterm point you agree. Under FOB or EXW the factory's clock ends at the port or door and the logistics clock starts; under DAP the factory's schedule absorbs the freight. Compare quotes only under the same term, because different terms are different scopes of the same order.

What should the handover documents carry to keep the schedule moving?

The commercial invoice, packing list and any certificate your destination requires, prepared to your format so customs does not stop for a correction. Document mismatches are the most common customs delay, and they are preventable by agreeing the format at the order stage.

How much time should I add between the factory's date and my hard need?

A margin covering the realistic variation of the longest leg. A few days suffice when the freight is air and the factory leg is reliable; a week or more is needed for sea freight or shipments landing near holidays. Hold the margin between the estimated arrival and your hard need, not inside the factory's promise.