When a shop carries one or two SKUs, inventory can live in your head. Once the catalog grows to ten, twenty, or more, each with its own lead time, sell rate, and capital requirement, running without a system means the same two problems rotate endlessly: stockouts that lose sales, and dead stock that locks up cash.
Why many SKUs break the informal approach
With one product you naturally notice when the shelf is getting thin. With twenty you cannot watch them all at once. That is not a discipline failure. It is a capacity problem: the number of SKUs exceeds what unstructured attention can cover.
Three failure modes show up when there is no system:
- Stockout you did not see coming. A slow-moving SKU sits quietly in the warehouse and you stop thinking about it. By the time you check, stock is at zero, orders are waiting, and you are canceling purchases or refunding deposits. Shop rating takes a hit.
- Panic overstock on a winning SKU. A product is running well, so you load up heavily out of fear of running out. The trend cools in a few weeks and you are sitting on hundreds of units you cannot move. That capital cannot go anywhere else.
- Wrong reorder sequence. You spend available capital restocking a C-tier SKU while an A-tier one is three days from zero. By the time the A-tier runs out, the money is already tied up in something that was not urgent.
All three problems share one root: no clear picture of which SKU needs action first.
Building a simple stock-visibility system
The first step is having one place that shows real on-hand quantity for every SKU, updated regularly. You do not need expensive software to start. A spreadsheet with a handful of columns is enough:
- SKU name
- Current on-hand quantity
- Average daily sales (trailing 14 to 30 days)
- Real lead time for that SKU (from order placed to stock received in your warehouse)
- Days of stock remaining at current sell rate
That last column is the most important one. Divide current on-hand by average daily sales and you get days remaining. If you have 120 units and sell 8 a day, you have roughly 15 days left. If the lead time for that SKU is 25 days, you are already 10 days late on the reorder.
Update this sheet at minimum once a week. Many shops run through it every Monday morning. One pass and you know what needs attention that week.
Reorder points: where to set them
A reorder point is the on-hand quantity that, when you hit it, means you must place an order immediately. Not "probably soon." Immediately. It is the level where, if you order right now, stock will arrive just before you run out under normal conditions.
The basic formula:
Reorder point = Average daily sales x Lead time in days
A worked example: a SKU selling 10 units a day, with a real lead time of 22 days (factory production 3 to 5 days, consolidation and packing 2 days, sea freight roughly 18 to 25 days, customs clearance and delivery to your warehouse 2 to 3 days). Minimum reorder point is 220 units.
That covers normal conditions. If you run promotions or livestreams that can double sell-through for a few days, add a buffer. A common rule is 20 to 30 percent on top of the base figure, so that example becomes around 265 to 285 units.
Each SKU has its own reorder point because lead times and sell rates differ. Two SKUs from the same supplier can have very different thresholds if one sells fast and one moves slowly.
Classifying SKUs so you know where to focus
Tracking twenty SKUs with the same intensity is both exhausting and unnecessary. Grouping by revenue contribution tells you where tight control actually pays.
A simple split by revenue over the last 30 days:
- Group A: Roughly 20 percent of your SKUs, contributing around 70 to 80 percent of revenue. These cannot be allowed to stock out. High reorder points, thick safety buffer, daily attention.
- Group B: About 30 percent of SKUs, adding another 15 to 20 percent of revenue. Weekly monitoring, standard reorder points.
- Group C: Everything else, contributing very little. This is where capital most often gets trapped. Keep on-hand quantities lean, order smaller batches, and regularly ask whether each SKU still earns its place.
This classification is not permanent. A C-tier product can jump to A if a trend breaks its way, and an A-tier can slide to B as a category saturates. Review the groupings every one to two months.
Avoiding dead stock
Stockouts cost you sales. Overstock costs you in a different way: capital locked in the warehouse cannot be reallocated to a SKU that is running low or an opportunity that just appeared.
A few rules that help:
- Order to actual sell rate, not projected sell rate. The trailing 30-day figure is a fact. "We plan to push this harder" is not. Source against the fact first, and only increase when you have evidence the rate has actually changed.
- Set a maximum stock ceiling for each SKU. Decide the most months of stock you are comfortable holding, multiply by monthly sell rate, and do not exceed that when placing an order. For goods imported from China, most shops find 45 to 60 days of cover reasonable. Holding more than 90 days of cover on most SKUs is worth questioning unless there is a specific reason (seasonality, very long lead time).
- Watch for a declining sell rate. If a SKU has been selling less each month for two or three months straight, do not reorder at the same quantity out of habit. Check whether the market has shifted before putting more money in.
Selling one SKU across multiple platforms
If you list the same SKU on both TikTok Shop and Shopee, the real inventory is a single pool but each platform shows a separate number. When both channels sell hard at the same time, it is easy to commit the same unit twice.
The simplest way to reduce this risk without software: allocate real stock between platforms in proportion to how each channel typically sells, and update manually at least daily or after any large order. If real on-hand is 200 units and TikTok Shop historically drives about 60 percent of volume, put 120 on TikTok Shop and 80 on Shopee. When total orders start closing in on actual stock, lower the displayed quantity on both platforms simultaneously, not one at a time.
This approach is imperfect but low-friction. When daily order volume grows large enough that manual updates consistently lag behind reality, that is the signal to look at inventory sync software.
Bottom line
Managing inventory across many SKUs is not technically complicated, but it does require a system or the same problems keep coming back. Know the reorder point for every SKU, keep on-hand figures current, and classify your catalog so energy goes toward the SKUs that actually drive the business. Start with a simple spreadsheet. Add tools only when the spreadsheet genuinely stops being enough.