perpetual inventory

Here is a mistake many shop owners make without knowing it has a name. They restock, sell, restock again, and only count what is left on the shelf once a month or once a year, trusting memory and guesswork in between. By the time they count, they cannot explain why fifteen bags of rice have simply vanished, and they shrug it off as spoilage or theft without ever knowing which.

Perpetual inventory fixes that gap by recording every single movement as it happens. Every sale, every delivery, every return updates the stock figure immediately, in real time, so the number on the system always matches, or should match, what is physically sitting in the store.

Take a provisions store in Yaba that sells cartons of milk. With a perpetual system, the moment a carton is sold, the software deducts it from stock and records the cost of that carton against the sale. The owner does not wait until the end of the month to guess how many cartons are left. She checks her phone and knows instantly, and if the number does not match what is on the shelf, she knows immediately something needs investigating, not three weeks later.

A UK example works the same way. A small bookshop in Leeds using a point of sale system sees its inventory count fall by one the second a customer buys a novel at the till. No manual stocktake is needed to know what remains, though occasional physical counts still happen to catch things the system cannot see, like a damaged book calmly binned by staff.

The alternative, periodic inventory, only updates stock levels when someone physically counts everything, often monthly or yearly. It is cheaper to run but leaves you blind in between counts, which is exactly how small losses grow into big unexplained gaps.

Perpetual inventory costs more to set up, usually needing barcode scanners or software, but it gives owners and investors a much clearer, almost live consider of what a business actually holds and what that stock is truly costing it.