Shopify Inventory Replenishment: Complete Guide

Reorder point, reorder quantity, ordering cadence, which SKUs to check first, whether to automate any of it — each of those is its own decision, with its own formula or rule of thumb, and each one has its own post on this site. Replenishment is what happens when you put all five in a sequence and run that sequence every week, for every SKU, without dropping any of them.

This guide is the map. It doesn't re-derive any single formula, since each section links to the post that already owns it, but it puts the five decisions in the order they actually happen in, so the individual pieces read as one process rather than five unrelated articles.

What replenishment means

Replenishment is the operational half of keeping stock available: given what you expect to sell, decide when to order, how much, how often, and in what priority. It sits downstream of forecasting: Shopify inventory forecasting answers "how much will I sell," and replenishment takes that number and turns it into actual purchase orders. This guide treats the forecast as an input already in hand, not something to derive again here.

The common failure mode isn't getting any single formula wrong. It's treating replenishment as a setup task done once at launch rather than a loop that has to keep running. Velocity drifts, suppliers slow down, a SKU that sold steadily for a year suddenly doesn't. A strategy built to be recalculated survives that. A strategy built to be set once doesn't.

Building a replenishment strategy

A replenishment strategy is the five decisions below, made once as a framework and then applied consistently, rather than re-decided from scratch every time a SKU runs low:

Each one is covered in full in its own post below. What matters here is the order they happen in: a reorder point without a quantity method tells you when but not how much; a cadence set without prioritization treats a two-dollar accessory the same as your best-selling SKU. The strategy is the sequence, not any single formula taken in isolation.

The reorder point

The reorder point is the stock level that triggers an order: lead-time demand plus a safety buffer, calculated per SKU rather than guessed at. The reorder point formula guide covers the full formula, a worked example, and a diagram of one complete reorder cycle; this guide assumes you have that number rather than deriving it again. It's worth noting this is a different, calculated number from a native low-stock alert, which fires at a fixed threshold rather than one computed from actual sales velocity and lead time.

For the running example used throughout this guide's spoke posts (a candle called "Cedar & Fig, 250g," selling 5 units a day with a 12-day supplier lead time), that formula lands the reorder point at 90 units.

The reorder quantity

Once a SKU crosses its reorder point, the next question is how much to order. Reorder quantity: how much stock to order covers the formula, target stock level minus what's on hand and on order, plus what changes once you round to a supplier's minimum order quantity or case pack. It's a deliberately simpler approach than the classic Economic Order Quantity formula, which needs ordering-cost and holding-cost figures few small stores track with any precision, and which assumes constant demand, an assumption seasonal and promo-driven SKUs routinely break.

Because Shopify already tracks inventory continuously rather than through a scheduled count, this kind of trigger-based reordering fits the platform naturally: you're not waiting for a periodic review to notice a SKU has crossed its line, the way older systems built for manual stock checks were designed to.

For the terminology mix-up this causes, reorder point vs. reorder quantity puts the two numbers side by side on one SKU. Some older systems bundle both into a single pair of numbers instead; see min/max inventory planning explained for how that maps onto the same two concepts.

Choosing your cadence

The reorder point tells you when a specific SKU needs attention. Cadence is a separate, calendar-level decision: how often you sit down and place orders at all — weekly, monthly, or tied to a supplier's minimum order quantity. Order too often and small, frequent orders eat into supplier discounts and shipping efficiency; order too rarely and cash sits in stock you didn't need yet. How often should you reorder inventory? covers that trade-off in full, including how a longer cadence changes the target-stock-level number above.

Prioritizing what to reorder first

Not every SKU earns the same weekly scrutiny. A small share of SKUs usually accounts for most of a store's revenue, and those are the ones worth checking on a tight cadence with a conservative safety buffer; slower movers can be reviewed less often with a looser one. How to prioritize products for reordering covers grading products by revenue contribution and applying that grade to your review routine, rather than reviewing two hundred SKUs with identical care every week.

Automating the process

Every step above can be run by hand in a spreadsheet, and for a small catalog, that's genuinely fine. The work stops scaling once a store carries enough SKUs that recalculating velocity, checking lead times, and reviewing reorder points for all of them every week becomes a part-time job on its own. Automatic vs. manual inventory reordering covers where that line tends to fall and what changes once you cross it.

That's the gap StockCue is built to close: it recalculates reorder points from live sales data every night, on every plan including Free, and on Starter and up turns a crossed reorder point into a sized purchase order ready to send, with each supplier's MOQ and case pack already applied. How to automate reorder recommendations covers what to look for in automation software generally, not just this one.

Frequently Asked Questions

What is inventory replenishment?

Inventory replenishment is the process of deciding when to order more stock, how much, how often, and in what priority order across a catalog. It's the operational sequence that turns a demand forecast into actual purchase orders.

What's the difference between replenishment and forecasting?

Forecasting answers how much you expect to sell. Replenishment takes that forecast and turns it into decisions: when to order, how much, how often, and which SKUs to check first. Forecasting is the input; replenishment is what you do with it.

How do you build a replenishment strategy for a Shopify store?

Set a reorder point per SKU from its own sales velocity and lead time, decide a reorder quantity method, pick an ordering cadence, prioritize which SKUs get reviewed most often, and decide how much of that process stays manual. Each decision has its own formula or rule of thumb; the strategy is running them in sequence, consistently, rather than solving each SKU from scratch.

When should replenishment be automated?

When the manual version stops being sustainable — typically once a catalog grows large enough that recalculating velocity, checking lead times, and reviewing reorder points for every SKU every week takes longer than the margin on slow-moving items justifies. There's no fixed SKU count that applies to every store; it's the point where the maintenance itself becomes the job.