What is stock, and how do you manage it without running out or overstocking? (for online shops)

Stock is the quantity of goods the shop actually has on hand right now. Stock management means always knowing how many of each item are left, where they are and when to reorder. There are two goals: don't sell what you don't have (stockouts), and don't hold items that won't sell for too long (dead stock).

Why stock goes wrong more easily for online shops than physical stores

Most online shops sell on several channels at once, such as Shopee, Lazada, TikTok Shop and LINE or Facebook chat. The same item has its quantity set separately in each place. Sell one on one channel, forget to reduce it on another, and you end up overselling: you have to cancel the order, the customer is disappointed, and some marketplaces even count it against your shop's rating.

3 terms worth knowing

• On-hand stock — what is physically in the warehouse and can be counted by hand
• Available-to-sell stock — on-hand stock minus items customers have ordered but that haven't been packed and shipped yet (reserved). This is the number every sales channel should show
• Reorder point — the minimum level at which you must reorder immediately, so new stock arrives before the current stock runs out

How to set up product codes (SKUs) that are easy to use

A SKU is a code the shop assigns to each product variant, with a separate code for every colour and size. Setting them up well from the start makes searching, counting and making barcodes much easier.

• Start with the product group, then the style, colour and size, e.g. TS-WH-M = T-shirt, white, size M
• Use only English letters, numbers and hyphens — no spaces and no Thai characters
• Keep codes the same length across the shop, and never reuse a code from a discontinued product
• Use the same code on every channel so stock is deducted consistently

A simple way to calculate the reorder point

A formula small shops can use right away: Reorder point = average daily sales × days waiting for stock + safety stock

Example: white T-shirts sell 5 a day, the factory takes 7 days to deliver, and you want 10 extra as a buffer in case sales pick up. Reorder point = 5 × 7 + 10 = 45. So whenever you're down to 45, place a new order.

How to do a stock count, step by step

• Pick a time when nothing is coming in or going out, e.g. after you stop taking orders or in the morning before packing
• Print a list of all SKUs with the quantities in your system/file
• Count shelf by shelf and write down the actual quantity (a barcode scanner is faster and causes fewer errors)
• Compare with the file, find the items that don't match and look for the cause, e.g. a return or damaged item that wasn't recorded
• Adjust the figures to match reality, and note the reason every time

You don't need to count the whole shop every day: a full count once a month is enough, but bestsellers and high-value items should be counted every week, because mistakes there cost a lot.

Dead stock costs more than you think

Items that don't sell are money sitting on the shelf. For example, 30 shirts that cost 120 baht each = 3,600 baht tied up, not counting storage space and items deteriorating.

• Every month, check for items with no sales for more than 60–90 days
• Clear them with bundle deals (paired with a bestseller), discounts or as free gifts
• Order less next time, or stop ordering that item
• For items that can expire, sell what came in first, first (FIFO)

5 steps to managing stock for a small shop

• Give every item a SKU, separated by colour and size
• Record every movement: goods received, sales, damaged items, returns — never edit the on-hand number directly without a source
• Set a reorder point for each item and check the "running low" list every week
• Do physical counts on a cycle and adjust the figures to match
• Look for items that haven't moved for more than 60–90 days and run a clearance promotion before they become dead stock

You can start with Excel for free

Excel vs a stock system: what's the difference?

• Deducting stock — Excel: you type it in for every order · System: whichever channel sells, the central stock is deducted automatically
• Multiple channels — Excel: you have to update quantities on each marketplace one by one · System: quantities are pushed back to every channel
• Several people at once — Excel: file conflicts, numbers easily go wrong · System: everyone sees the same numbers
• Cost — Excel: free · System: both free and monthly paid options

Signs it's time to stop using Excel

• You sell on more than one channel and have to update product quantities everywhere yourself
• You've oversold and had to cancel orders
• Several people help pack orders, but the numbers in the file don't match what's on the shelf
• You have many product options (colour × size) and the file has become long and full of typos

If any of these sound familiar, AooCommerce's inventory system uses one central stock: whichever channel makes the sale, it's deducted in one place. It keeps a history of goods received and issued and alerts you when items are running low. You can start for free.