Running out of stock mid-campaign is not bad luck. It is the result of underestimating lead time and reordering too late. This is about adding up every leg to get the real number, and placing the reorder point where it actually belongs, not after the shelf is nearly empty.
The lead time on 1688 is not your lead time
When a 1688 supplier says "3 to 5 days to ship," they mean the time from when they receive the order to when goods leave their factory or warehouse. That is one leg. There is a long road from "goods out of the factory in China" to "goods in your warehouse in Vietnam."
Many shop owners take that supplier number, add a few days for international shipping, and call it done. In practice, between the factory gate in China and your receiving dock in Vietnam, there are at least four to five separate legs, each with its own timing, each capable of adding delay.
Every leg of a 1688 order
To calculate correctly, list each leg first:
- Supplier processing time. From when you place the order to when they actually start packing and hand goods to domestic shipping. This runs from 1 day up to 3 to 5 days depending on the factory and the season. During peak periods before Chinese New Year or the 11/11 shopping festival, processing times stretch noticeably.
- Domestic China shipping to the consolidation warehouse. From the factory to a consolidation warehouse in cities like Guangzhou, Shenzhen, or Yiwu. Usually 1 to 3 days under normal conditions. If the supplier is in a more distant province, budget 3 to 5 days.
- Time at the consolidation warehouse. The warehouse receives goods, checks them, repacks, and waits until the shipment is ready to dispatch. Roughly 1 to 3 days if everything arrives on schedule. If you are consolidating from multiple suppliers, this leg waits for the last parcel in.
- International freight from China to Vietnam. This is the biggest leg, and it varies widely by route:
- Air express: 3 to 7 days (meaningfully higher freight cost; works for small, light, high-value goods).
- Road or rail via border crossings: roughly 5 to 12 days depending on the route and how busy the crossing is.
- Sea freight: 18 to 30 days is a realistic range depending on origin and destination port. Good for heavy or bulky goods where time is not the constraint.
- Customs clearance and last-mile delivery. After goods enter Vietnam, they still need customs inspection, duty payment on formal imports, and then the carrier delivers to your address. Under normal conditions this is 2 to 5 days, but during peak seasons or when a shipment is pulled for detailed inspection, it runs longer.
Adding all of this up at a typical mid-range estimate: a standard road-route shipment takes around 15 to 25 days from order placement to goods in your warehouse. Sea freight can be 35 to 45 days or longer if anything goes wrong. Air is faster, but not every product can absorb the freight cost.
Why you need a buffer on top of that
The ranges above assume nothing goes wrong. In practice, something goes slightly wrong on a meaningful share of shipments:
- The supplier runs slower than expected because a larger order came in ahead of yours, or a material ran short.
- Goods arrive at the consolidation warehouse one or two days late, miss the scheduled consolidation run, and wait for the next one.
- The border crossing backs up over a weekend or a Chinese public holiday.
- Vietnam customs holds the shipment for additional inspection, especially for a product category with no clearance history.
For planning purposes, do not use the average. Use the average plus a 30 to 40 percent buffer. If your typical road shipment runs 20 days, plan for 27 to 28 days. If sea freight typically runs 35 days, plan for 45 to 50.
That buffer is not waste. It is the cost of certainty. Stock arriving 3 to 5 days early causes no problem. Stock arriving 10 days late while you are already out mid-campaign is a real problem.
The reorder point: working backward from when you will be empty
Once you have a realistic lead time (including the buffer), the next step is to use it to set your reorder point: the inventory level at which you must place a new order immediately.
The basic formula:
Reorder point = daily sales rate x lead time in days
For example: a SKU selling 30 units per day with a realistic lead time of 25 days gives a reorder point of 750 units. When stock touches 750, you place the next order. The new stock arrives just as you sell the last unit.
If you want a layer of safety stock on top of that, to absorb a day where ads fire well and you sell 60 instead of 30, add roughly 5 to 7 days of average sales on top. The reorder point becomes 750 + 150 = 900 units.
The right numbers differ by SKU. A steady, predictable seller needs a smaller buffer. A SKU where ad spend drives spiky demand needs a larger one.
Common mistakes when calculating lead time
A few errors come up repeatedly:
- Using the best-case lead time instead of the realistic one. One shipment arriving in 14 days does not mean every shipment will. Use an average across several orders, not the fastest outlier.
- Forgetting the customs and last-mile leg. Many operators calculate up to "goods arriving in Vietnam" and stop. But from the port or crossing to your warehouse still adds days that count.
- Not updating lead time after changing supplier or route. A new supplier in a different province, or a new shipping route, will have different timing. Recalculate rather than reuse the old number.
- Not separating seasonal lead times. Lead time during Chinese New Year (when factories close for 7 to 15 days) and during the 11/11 period (when consolidation warehouses and freight are congested) is meaningfully different from ordinary months. Keep separate estimates for each.
Lead time when consolidating from multiple suppliers
If one shipment pulls goods from several different suppliers and merges them at a consolidation warehouse, the effective lead time for the whole batch is set by the slowest supplier, not the average. The last parcel to arrive triggers consolidation and dispatch.
In practice this means:
- Ask each supplier about their processing time before confirming the order.
- Notice which supplier consistently runs slowest and either order from them first or wait for their confirmation before coordinating the rest.
- Have a plan to split the shipment if one source is running significantly late rather than holding the whole batch.
If you consolidate from five suppliers, four arrive on schedule and one runs 4 days late, the entire shipment is 4 days late. This is easy to miss when the calculation lives in a spreadsheet rather than in the physical flow.
Bottom line
Your real lead time is not the number the supplier lists on the product page. It is the sum of every leg from order placement to goods in your warehouse, plus a realistic buffer for the portion of shipments that do not go smoothly. Get that number right, set your reorder point from it, and you stop ordering in a panic when the shelf is nearly empty. You order because the math told you to, before you needed to.