Every few weeks a seller writes in with the same sentence: "I ordered early this time, and we still ran out in the fourth week." The question that follows is always the same one — early compared with what?
A booking date is not a lead time. What decides whether the shelf stays full is the stretch between the purchase order and a unit that can actually be picked, and that stretch is made of four clocks. Most sellers only count the middle one.
Four clocks, not one
- Production. 25–35 days for standard consumer goods. In the month before Lunar New Year factories stop taking orders, and the same run takes 40–45.
- First leg. Sea from Shenzhen to Los Angeles door to door: 30–38 days. To New York: 33–42. Rail to Europe: 22–28. Cross-border road: 12–16. Air: 5–8.
- Arrival and release. 3–7 days from vessel arrival to a container you can collect; 7–10 in months when the exam rate is high.
- Warehouse receipt and put-away. 2–5 days when the appointment is booked ahead; 7–10 in the fourth quarter if you book late.
Add them up honestly and a "45-day" sea shipment becomes a 75-day decision. That gap is where most stockouts come from — not from the ship leaving late.
What each mode really costs you in time
| Mode | Door to door | Cost | Where it fits |
|---|---|---|---|
| Sea, full container | 30–38 days to the US west coast, 33–42 to the east coast | Lowest per kg | Baseline volume, bulky goods, two months of cover or more |
| Sea, LCL | 35–45 days | 1.5–2 times FCL per cubic metre | New SKUs under about 8 CBM, test batches |
| Rail to Europe | 22–28 days | Around 60–70% of air | European restock with two weeks to spare |
| Air freight | 5–8 days | 5–7 times sea | Launch stock, top-up when a best seller runs ahead |
| Courier | 3–5 days | Highest per kg | Samples, returns, single units |
Put one number on it
Take a seller doing 40 orders a day on one SKU, restocking every 30 days by sea, with 30 days of safety cover and a 35-day door-to-door transit.
Reorder point = daily sales × (lead time + safety cover) = 40 × (35 + 30) = 2,600 units.
If those orders land in the middle of a cycle, add half a restocking interval: 40 × (35 + 30 + 15) = 3,200 units. That is what has to be in stock or already on the water on the day you place the order. If it is not, the gap shows up three weeks later and lands on the forwarder's desk.
Stockout and overstock are both invoices
- A stockout costs the ranking and the ad weight you already paid for. Seven to fourteen days to recover in a normal month; a whole season for a seasonal SKU.
- Overstock costs cash and storage, charged per CBM per month plus a peak surcharge — and the goods may be out of date before they sell.
- Which mistake is cheaper depends on margin. High margin and fast turnover: carry more. Low margin and bulky: carry less, and pay for air on the gap.
The 70/30 split most sellers end up with
Volume by sea, a top-up by air or road for launches and for best sellers in their first month. It is not a rule; it is what the arithmetic produces once a stockout costs more than the air freight. Run the sum with your own numbers and the split tends to land near 70/30 without anyone choosing it.
Three places the sum goes wrong
- Counting from the factory's ready date instead of the next available sailing — booking, trucking and cut-off all sit in between.
- Using one average lead time for every SKU. A slow mover and a best seller do not share a reorder point.
- Leaving peak season out of the buffer. The booking that took 35 days in March takes 45 in November, and the warehouse appointment is harder to get.
A plain note from the desk: the date on the purchase order is not the date that matters. The date the goods become pickable is — count the four clocks backwards from there, and "I ordered early" stops being a sentence anyone needs to say.
If you would like a second pair of eyes, send your daily order volume, SKU count, the mode you use now and the door-to-door days on your last shipment to us on WhatsApp. We will put the four clocks on one timeline and tell you where the next order point actually falls.