Selling online and in store: what to check so your inventory stays accurate

A customer buys the last one of an item online on a Saturday evening, the very item you sold in the shop that same afternoon. Now there is an order to cancel, a refund to issue, and an apology to write. This kind of mix up happens often to merchants who sell both in a physical store and online, and the cause is almost always the same: the system running the online store did not know, at the moment of the in store sale, that the stock had just dropped.

The problem is not rare, and it is almost always avoidable once you understand how your own system actually keeps stock counts in step across sales channels.

What 'synced' actually means

Two systems sharing the same stock count do not necessarily update each other in real time. Some update the number the instant a sale closes, no matter the channel. Others update in batches, on a fixed schedule, or only when the till closes for the day. Between updates, the stock shown online can stay wrong for several minutes, sometimes longer.

Take a simple example. A shop selling the same product in store and through an online store starts the day with ten units on hand. If seven sell in store over the afternoon and the online count does not change until closing, nothing stops a customer from ordering five more on the site in the meantime. The problem only shows up when orders are being prepared, and some of them simply no longer exist.

Even a point of sale system built for this kind of use does not remove that risk automatically. According to Clover's own technical documentation, updating an item's stock across multiple locations or channels is not a single action: each location has to be updated separately, or the link has to run through a connected app built for that purpose. A merchant who assumes the system handles it without checking exactly how can end up selling the same item twice without knowing it.

The risk is higher still when the online channel is not tied to the till through the same provider, for instance a storefront built separately on a social network. In that case there is no automatic sync at all: updating stock on both sides becomes a manual task, or an accepted risk.

What happens when stock hits zero

The second thing worth checking is what your system does the moment an item hits zero. The answer differs from one platform to another, and it is worth knowing before a customer finds out for you.

• The item disappears from the site automatically, with no action on your part.
• It stays listed, but marked out of stock or back ordered.
• It stays fully purchasable, with no warning, until someone corrects the number by hand.

The third outcome is the costliest one, since it turns a simple stock gap into a cancelled order and a customer to reassure. Many platforms let you set a safety threshold, for instance treating an item as sold out online while one or two remain in the shop. Checking whether that setting exists, in your inventory settings, is a good place to start.

Counting by hand, on a regular schedule

Even the best sync setup does not replace an occasional physical count. Discrepancies build up: a return logged incorrectly, a damaged item never removed from the system, a data entry mistake when a delivery comes in.

The Business Development Bank of Canada recommends counting a sample of products on a regular basis, often daily or weekly, rather than one full count a year. This method, sometimes called cycle counting, is meant to catch a discrepancy before it causes a problem, not to recount everything at once.

Picking a fixed day of the week for this count, rather than waiting until something looks wrong, makes the habit easier to keep up over time.

For a business that also sells online, the best candidates for this kind of check are items sold on both channels at once, particularly ones running low. Those are the items most at risk of a double sale.

A minority channel, with little room for error

In Canada, online retail sales made up 7.0% of total retail trade in April 2026, a slight dip from 7.1% in March, according to Statistics Canada. For most retailers, online sales remain a minority share of overall revenue.

That modest share does not make it less important to manage well. A cancelled online order rarely gets settled quietly. The customer leaves a review, posts publicly, or simply does not come back. So the effort worth putting in depends less on total online sales volume than on how many items sell on both channels at once.

The question to ask your provider

Before your next busy stretch, ask your point of sale or online store provider exactly when stock updates on the other channel after a sale: instantly, or after a delay. If there is a delay, find out how long it usually runs. The answer tells you whether your top sellers on both channels need a safety threshold, and what that threshold should be.