The inventory planning process: a monthly cadence for small Shopify stores

A workable inventory planning process for a small Shopify store is seven steps on a monthly loop: review last period's actuals, forecast demand per category, budget the buy, build the SKU-level buy list, place purchase orders with order-by dates, receive and reconcile, then monitor weekly in between. Big retailers run this as a formal process; a 500-SKU store can run it in one focused afternoon a month plus ten minutes a week. What kills it isn't complexity — it's skipping a step and finding out at the worst moment.

Here's each step with what it produces, how long it should take, and where stores commonly break it.

Step 1: Review last period's actuals (30–45 min, monthly)

Before forecasting anything, look at what actually happened: sales by category, what went out of stock, what didn't move, and what you received late.

Pull from Shopify: sales by product over the trailing period, and your inventory history. Two things deserve explicit attention:

• Out-of-stock periods. A SKU that sold 40 units in a month while being dark for 10 days didn't sell 40 — it sold out, and demand was higher. Those zero-days weren't low demand; they were missing data. Note which SKUs had availability gaps so your forecast doesn't inherit them.
• What arrived late. Compare planned receipt dates on last month's POs against actuals. This is where your supplier lead-time assumptions get calibrated — if you assume 30 days and reality is 42, every downstream order-by date is wrong.

Output: a short list — categories up, categories down, SKUs that went dark, suppliers that slipped.

Step 2: Forecast demand per category (30–60 min, monthly)

You don't need a forecasting model. At this scale you need a per-category growth judgment anchored in data:

• Last month's unit sales per category, corrected for the out-of-stock gaps from step 1 (add back estimated missed sales on the dark days).
• Same month last year, if you have the history, for seasonality.
• Known events: promotions you've scheduled, a new product launching, seasonal ramps. BFCM planning, for instance, moves the whole calendar — it has its own timeline covered in our BFCM inventory planning guide if that season is approaching.

Write the forecast down as units per category per month. One number per category, with a one-line reason. If you can't state the reason, the forecast is a guess wearing a suit — that's fine, but label it, because step 3 treats confident and unconfident forecasts differently.

Step 3: Budget the buy (30 min, monthly)

This is open-to-buy logic: how much inventory you're allowed to add, given what you already own and what you plan to sell.

The plain-English version:

Planned purchases = planned ending inventory + planned sales (at cost) − current inventory − already-on-order

Example for the "drinkware" category, November planning done in late October:

• Planned December ending inventory: $9,000 (you want to enter January at roughly your baseline)
• Planned Nov + Dec sales at cost: $7,500 + $8,500 = $16,000
• Current on-hand at cost: $11,000
• Already on order, arriving Nov–Dec: $4,200

OTB = 9,000 + 16,000 − 11,000 − 4,200 = $9,800 available to spend on drinkware POs

That $9,800 is a ceiling, not a target. The buy list in step 4 has to fit inside it. The full working, including how to set planned ending inventory, is in our open-to-buy guide.

Step 4: Build the buy list per SKU (60–90 min, monthly)

Now the category budget becomes actual SKUs and quantities. For each SKU worth buying:

1. Days of cover right now: units on hand ÷ average daily units sold — computed on in-stock days only, so recent sold-out periods don't fake a slow velocity.
2. Order-up-to quantity: forecast daily rate × (lead time + review period + safety days) − units on hand − units incoming. If the math reads as negative, you don't order this SKU this cycle. The full formula with worked numbers is in how much inventory to order.
3. Order-by date: today's date + (days of cover − lead time − safety days), roughly. The date matters as much as the quantity — a right quantity ordered late is a wrong decision.
4. Pack sizes and MOQs: reconcile the math against what the supplier actually sells in. A suggested order of 37 units against a case of 24 means 48 or 24 — decide which side of the rounding you'd rather be on.

Sort the list by urgency (order-by date) and check the total against the step-3 budget. If the list busts the budget, cut from the bottom: lowest velocity, lowest margin, biggest gap between suggested and MOQ quantity.

Output: a spreadsheet — SKU, on hand, velocity, lead time, suggested qty, order-by date, supplier. This list is the process's whole point; everything else feeds it.

Step 5: Place POs with order-by dates (30–45 min, monthly)

Turn list rows into purchase orders. Shopify has native POs linked to suppliers and inventory transfers (documented in the Shopify Help Center, accessed October 2026) — use them, or whatever system you'll actually check. Every PO needs:

• SKU, quantity, agreed unit cost
• Expected delivery date, not just "ASAP" — the date your lead-time math assumes
• Terms: deposit, balance, who arranges freight

Send, then calendar a follow-up per PO at the halfway point between send date and expected delivery. The supplier-silence-until-week-5 failure mode is entirely preventable.

Step 6: Receive and reconcile (30 min per delivery, as they arrive)

When stock lands: receive it against the PO, count what actually arrived, and record discrepancies. Short-shipments, wrong variants, and damaged units that go unrecorded poison every number downstream — your days-of-cover math, your cost data, your supplier scorecards. A monthly cycle count of a slice of your catalog catches the drift that receives miss; the method is in Shopify inventory counts.

Ten minutes of reconciliation at the dock saves an afternoon of forensic accounting in January.

Step 7: Monitor weekly (10–15 min, weekly)

The monthly loop needs a weekly tripwire between sessions:

• SKUs that went out of stock this week
• SKUs whose days of cover dropped below their lead time (these are already late — order today, don't wait for month-end)
• POs that haven't shipped on schedule

That's the list. Fifteen minutes, Monday morning, with a decision on each row. Skipping it is how the monthly meeting starts with "so, what's been on fire since we last talked."

The one-page checklist

Monthly (one afternoon, ~3–4 hours):

• Review: sales by category, out-of-stock gaps, late receipts (45 min)
• Forecast: units per category per month, with one-line reasons (60 min)
• Budget: open-to-buy per category (30 min)
• Buy list: SKU → cover → suggested qty → order-by date (90 min)
• POs: placed with expected delivery dates, follow-ups calendared (45 min)

Per delivery:

• Received against PO, discrepancies recorded

Weekly (Monday, 15 min):

• New out-of-stocks → decision
• Cover below lead time → decision
• Late POs → chase

If you want the weekly check partially automated: InventoryX's weekly Buying List is essentially steps 4 and 7 as a Monday email — SKU, days of cover, suggested quantity using your lead times, order-by date — though it won't run your forecasting or budgets for you; steps 2 and 3 stay yours.

Where small stores break this process

• Forecasts live in someone's head. Write them down, even badly. A written wrong forecast can be audited; a remembered one just re-forms.
• No budget step. Without OTB, every reorder feels individually justified and the total quietly doubles.
• Lead times are wishes. Use the last three actual receipt dates per supplier, not the quote from your first conversation.
• Weekly monitoring gets skipped in busy weeks — precisely the weeks when something usually goes out of stock.

This cadence is the operating layer on top of the fundamentals; if the foundations (locations, tracking, cost data) are shaky, fix those first via the Shopify inventory management guide before adding process on top.

Common questions

What are the steps in the inventory planning process? Seven: review last period's actuals, forecast demand per category, budget the buy with open-to-buy logic, build a SKU-level buy list with quantities and order-by dates, place purchase orders, receive and reconcile deliveries, and monitor weekly between monthly cycles. A small store can run the monthly portion in one afternoon; the weekly check takes about 15 minutes.

How much time does inventory planning take a small business? Budget roughly 3–4 hours monthly for a 100–5,000 SKU store: 45 minutes reviewing actuals, an hour forecasting, 30 minutes budgeting, 90 minutes on the buy list, 45 on POs. Add 10–15 minutes weekly for monitoring and 30 minutes per delivery for receiving. Automation of the weekly math can cut the recurring time further.

What's the difference between inventory planning and replenishment? Replenishment is the tactical question — when and how much to reorder a SKU. Planning is the budgeting and prioritization layer above it: how much you're allowed to buy per category this month and which SKUs make the cut. Reordering without the planning layer is how stores over-buy their bestsellers and under-buy everything else.

How far ahead should a small store plan inventory? One lead time plus one review cycle ahead, per supplier — roughly 2–3 months for domestic sourcing, longer for overseas. Forecasting twelve months out at this scale produces numbers too vague to act on; plan the next cycle in detail and hold a rough seasonal view for the rest.

Do I need software to run an inventory planning process? No — the process runs on exports and a spreadsheet, and most steps are judgment calls software can't make anyway. What software removes is the weekly recomputation: per-SKU velocity, days of cover, and order-by dates are mechanical math worth automating once your catalog passes a few hundred SKUs.

Next step

Don't build all seven steps at once. Run steps 4 and 7 this week — a buy list for your ten most urgent SKUs and a Monday check — then add the budget and forecast steps next month. The order-by-date math that anchors the buy list is worked out fully in how much inventory to order.