Set a Shopify low stock alert using days of cover rather than a fixed unit count. Multiply average daily sales by supplier lead time in days, add a safety buffer, and alert when stock falls below that figure. Ten units is six weeks of cover for one product and two days for another, which is why one number for the whole catalogue gets ignored.
Why this one is worth an interruption
The purpose of a low stock alert is to leave enough time to do something. That makes it a question about time, not about units, and a threshold expressed in units answers the wrong question.
A single catalogue-wide number produces two failures at once. On slow lines it fires constantly and trains people to dismiss it. On fast lines it fires after the decision point has already passed, which is worse, because the alert arrives looking useful and is not.
The threshold
Work in days of cover. The threshold is the stock level at which you still have time to reorder and receive before you run out.
| Condition | Set it to | Why that number |
|---|---|---|
| Reorder point | avg daily sales × lead time days | The stock that will sell while you wait for more |
| Safety buffer | add 20 to 50 per cent | Covers demand variation and a late supplier |
| Fast movers | review monthly | Sell-through changes faster than you think |
| Promoted lines | double the buffer | Ad spend distorts the daily average |
| Long lead time imports | measured lead time, not quoted | The quoted figure is usually production time only |
If you only change one thing, change it for your ten fastest-moving products. That is where a wrong threshold costs actual revenue rather than attention.
Who should receive it
Send it to whoever can actually place an order or pull stock from another location. Everyone else gets it in a daily summary.
- The person who raises purchase orders. They are the action.
- Whoever is running paid ads on that product, because pausing spend is often the faster fix than reordering.
- Not the whole team. A stock alert seen by six people is acted on by none of them, and read past by all of them.
What to do when it fires
- Check whether the product is currently being advertised, and pause the ad set if it is.
- Check other locations before ordering, because a transfer is faster than a supplier.
- Raise the purchase order, using measured lead time rather than the quoted figure.
- If neither is possible, decide now whether to let it go out of stock or switch it to backorder, and say which in the room.
When not to set this alert
Do not set this on a line you are discontinuing, on made-to-order products, or on anything where running out is the plan.
Do not set it on products with fewer than a handful of sales a month. The average daily sales figure is too noisy to produce a meaningful threshold, and the alert will fire on random variation. Review those on a monthly cycle instead.
Where the number comes from
The inputs are two things you already have. Average daily sales over a recent window that reflects current demand rather than last year's. And the elapsed time from deciding to reorder to stock being sellable, which is longer than the number your supplier quotes because it excludes acknowledgement, shipping and your own receiving.
Measure the second one rather than accepting it. Two dates per purchase order, sent and sellable, over six orders gives you a distribution that beats any quote.
Common questions
What is a good low stock threshold in Shopify?
One derived from that product's own sell-through and supplier lead time, not a catalogue-wide number. Multiply average daily sales by lead time in days and add a buffer of 20 to 50 per cent.
Why do my low stock alerts get ignored?
Almost always because one fixed number is applied to products that sell at very different rates, so the alert fires constantly on slow lines and too late on fast ones. People learn to dismiss it, then miss the one that mattered.
Who should get low stock alerts?
Whoever can place a purchase order or move stock between locations, plus whoever controls ad spend on that product. Sending it to the whole team reliably means nobody acts.
Should the threshold change during a sale?
Yes. Promotional demand breaks the average the threshold was built from. Raise the buffer before the campaign starts rather than reacting once it is selling out.