When to reorder on Shopify: reorder point, stockout date and how many to buy.

Reordering on Shopify after Stocky

Stocky was Shopify's own inventory app for purchase orders, stock counts and replenishment. Shopify has removed it from the App Store and says it is no longer available after 31 August 2026.¹ Its migration guide points to features in the Shopify admin instead:²

• Purchase orders and suppliers, created and received in the admin.
• Low-stock alerts, set up as automations in Shopify Flow.
• Stock reports through Analytics and custom explorations.
• Forecasting help from Sidekick, which Shopify says can suggest what needs replenishing and draft a transfer or purchase order within your minimum and maximum limits.

What none of these hands you is a reorder point per product that you can check. The method below gives you one, with numbers you can verify from your own reports.

Find what will run out, in Shopify admin

Both reports are under Analytics › Reports, in the Inventory category.³

1. Inventory sold daily by product gives the average units sold per day for each variant in the period you choose.³ Run it for the last 30 days and again for the last 90.
2. Inventory remaining per product divides the stock still in inventory by that daily average, giving days of inventory remaining.³ Sort it from lowest to highest.
3. For the variants near the top, check the Incoming quantity on the Inventory page. Incoming stock comes from transfers, purchase orders or apps and cannot be sold until it is received.⁵
4. Compare days left with your supplier's lead time. Anything with fewer days left than the lead time will run out before a reorder can land, even if you order today.

The formulas

Weighting the last 30 days at 60% follows a product that is speeding up or slowing down without letting one busy week decide. A plain 90-day average is fine for steady sellers. Counting incoming stock assumes it lands within the lead time; check the dates on the purchase order.

A worked example

An invented ceramic mug sells for $28.00. Your supplier takes 21 days from order to shelf, and you want each delivery to last 45 days.

Invented figures. Sales at risk uses the unrounded 11.217 days.

The mug passed its reorder point of 20 some days ago. Ordering today still leaves about 11 days without stock, so the useful moves now are the fast ones: transfer stock from another location if you hold any, and take the product out of paid campaigns until the delivery lands, so ad spend does not send people to a sold-out page.

Safety stock

Safety stock covers the days when sales run faster than average or the delivery runs late. Two common ways to set it:

• Days of cover. Safety stock = units sold per day × safety days. With 7 safety days the mug's reorder point becomes 0.92 × (21 + 7) = 25.8, so 26 units. Simple, and good enough for most catalogues.
• From the spread of daily sales. Safety stock = z × σ × √(lead time), where σ is the standard deviation of daily sales and z sets how often you accept running out: about 1.65 for a stockout in one cycle out of twenty. It needs clean daily sales history, and it only covers variation in demand, not in lead time.

Hold more safety stock on the products that carry the store and less on the long tail. An ABC analysis tells you which is which.

Alerts and purchase orders

1. Set a low-stock alert per product in Shopify Flow, the route Shopify recommends after Stocky.² Use each product's reorder point as its threshold, not one number for the whole catalogue: a fast seller needs to be reordered far earlier than a slow one.
2. Record every order as a purchase order in the admin, with the supplier, quantities and costs.⁴ The units then show as incoming, so your days-of-stock figures stop sending you to reorder the same product twice.⁵
3. Mark stock as received when it arrives, so it becomes available to sell.⁴
4. Recalculate monthly, and weekly for the handful of products that carry your sales.

Pitfalls

• Stockouts hide demand. Days when a variant was sold out count as days with no sales, so the rate comes out low and the next order is too small. Work out the rate over the days it was in stock.
• Quoted lead time is not real lead time. Use the time from placing the order to having the stock on the shelf, including production, customs and receiving.
• Promotions and seasons. A sale week inflates the 30-day rate; a quiet month deflates it. Adjust by hand around known events.
• Several locations. Total stock can look fine while the location that ships online orders is empty. Check the location that fulfils.
• Case packs and minimum orders. Round the quantity up to what the supplier sells, and treat the extra as cover.
• Slow sellers. For a product selling a few units a month, running out costs little and overbuying costs more. Save the attention for the fast ones.

Doing it automatically

Store Diagnosis is our free, read-only Shopify app. Each night it works out the selling pace of every active variant with the 60/40 weighting above, counts stock on hand and incoming, and flags every product that will run out before a reorder could arrive. It ranks them by the sales at risk, and each finding gives a reorder quantity for the lead time plus 45 days of selling, with the steps to place and record the order.

Two limits, stated in the report as well: it measures against a 21-day lead time for now, so if yours is longer more of your range is at risk than shown; and stock on a purchase order is counted as arriving in time. Variants selling fewer than about three a month are left out, because running out of them costs little.

Frequently asked questions