Before ordering another carton, check how long the stock you already own is likely to last.
You’ve paid the supplier, received the cartons and made room on the shelf. Until those products sell, some of your buying budget is sitting there with them. You need enough stock to fulfil orders, but an extra carton of a slow seller can leave you short of cash for a product customers want now.
Start with how long it might last
Days of stock is a rough planning measure calculated by dividing available units by average units sold per day. It is not a prediction. It gives you a common way to compare products that sell at different speeds.
Suppose you hold 120 units. If you sold 60 units over the last 30 days, the recent average is two units a day. At that pace, 120 units represents 60 days of stock. If another product also has 120 units but sold only 30 during the same period, it represents 120 days.
Both products have 120 units available, but Product B could take twice as long to sell through at its recent pace. If the supplier offers a bulk discount on B, weigh the saving against the extra stock you would have to hold. A lower purchase price can still mean more cash tied up.
Read the exceptions before the result
A recent promotion can inflate the sales rate and make stock cover look shorter than normal. A stockout can suppress sales and make demand look weaker than it really is. A new product may not have enough history for the average to mean much. Seasonal products need their own context.
Compare normal trading with normal trading. An 11.11 campaign or a Hari Raya promotion can change the pace for a Malaysian brand. Do not use that short burst as the permanent reorder rate. For cross-border supply, include production, freight and clearance in your lead-time estimate, using your own supplier history rather than a regional rule of thumb.
If the recent sales rate is zero, do not show zero days of stock. The calculation is undefined at that rate. Label it “no recent sales” and investigate. Zero days usually suggests nothing is available; that is the opposite of what a shelf full of unsold units tells you.
Lead time changes the decision
Sixty days of cover could be comfortable for a supplier that delivers in a week. It could be tight for a supplier that needs two months. Compare cover with replenishment lead time, and allow for variation in demand and delivery. The right buffer depends on the product and your business, not a universal number.
Also distinguish available stock from total stock. Units reserved for orders, damaged units and goods still in transit should not all be treated as ready to sell. If different systems use different definitions, write yours down before comparing their totals.
Choose a small, reversible action
Slow stock does not always need an immediate discount. Check whether the listing is complete, the product is visible and the price makes sense. Ask whether customers understand the use case. A poor photograph or an unavailable variant can leave a sellable product looking unwanted.
If you decide to clear stock, calculate what remains at the proposed price after product and selling costs. Do the same for a bundle. You might also pause the next purchase order while testing the offer. There’s little point clearing one batch if another oversized delivery arrives a week later.
Review the money, not just the units
Ten expensive units can tie up more cash than a hundred cheap ones. Put stock value at cost beside days of cover. That helps you prioritise the products with both a slow sales pace and a meaningful amount of cash committed.
Sources: Shopify inventory reports. Checked 10 October 2026. From 1 October, Shopify reports on-hand stock, including committed/unavailable units, and uses a 28-day average for days remaining. Our available-stock/30-day manual example is different.