Inventory Management for Growing Shopify Stores

By Claire. A Gold Coast supplements brand we’ve worked with for years called in a panic last November. They’d sold out of their hero product twice in three weeks, oversold a bundle that crossed three locations, and had a 3PL who kept finding stock that Shopify swore wasn’t there. The business was healthy. The inventory system was a mess. We spent six weeks helping them stabilise: location settings tidied up, low-stock alerts wired into Slack, a proper purchase order workflow, and eventually a move to Cin7 Core for forecasting. They haven’t oversold since. Here’s the playbook we used.

Start with the locations model

Shopify’s locations feature is the foundation of everything. Each location represents somewhere your inventory physically sits: a warehouse, a retail shop, a 3PL, a forward-deployed pop-up. Shopify can manage up to 1,000 locations depending on your plan, but most Australian merchants need three to ten. Get this layer right before you add complexity.

Common mistakes to avoid:

• Treating “in transit” as a location. It isn’t. Use a purchase order system or a dedicated app for inbound stock.
• Letting your 3PL hold the master record of truth. Shopify should be authoritative. The 3PL syncs to it.
• Creating a location for every dropship supplier. Use a single “Dropship” location with order-routing rules.
• Forgetting to set up location-based fulfilment priorities. Without them, Shopify picks somewhat randomly.

The single-location to multi-location transition

If you’re running a single warehouse and starting to consider a second location (maybe an east-coast warehouse to complement your Melbourne base, or a 3PL relationship for fulfilment scale), plan the transition carefully. The move itself is straightforward in Shopify: add the new location, transfer stock between locations using the Transfers feature, and update product availability per location.

What gets complicated is order routing. By default, Shopify tries to fulfil from a single location to minimise split shipments. You can override this with priority orderings or with apps like ShipperHQ for distance-based routing. For Australian merchants shipping nationally, the question is usually: does the cost saving of an east-coast warehouse outweigh the split-shipment cost when an order crosses categories?

Low-stock workflows that prevent stockouts

Stockouts cost more than the lost order. They damage trust, hurt search rankings (out-of-stock products fall in Google’s Shopping rankings), and often trigger refunds that eat margin. A proper low-stock workflow has three layers:

• Reorder thresholds defined per SKU based on lead time and sales velocity (Stocky and Inventory Planner both do this).
• Alerts that fire when stock crosses the threshold, routed to whoever places purchase orders.
• A weekly review meeting where someone actually looks at the alerts and acts.

Velocity changes seasonally. A summer-heavy product needs a different reorder threshold in October than in March. Recalculate quarterly at minimum.

3PL integration: the make-or-break of scale

When you outgrow self-fulfilment, picking the right 3PL and integrating them properly is one of the biggest operational decisions you’ll make. The Australian 3PL landscape has matured significantly: ShipBob, ShipHero, Hub Box, eStore Logistics, and a dozen others all offer native Shopify integration. The questions to ask are less about the brand and more about the fit:

• How real-time is the inventory sync? Sub-minute is ideal. Hourly batch syncs cause overselling.
• How are inbound shipments handled? Can you create an ASN in Shopify and have the 3PL reconcile?
• What are the SLAs for pick, pack, and despatch? Same-day is standard for Australian metro.
• How are returns processed? Do they update Shopify inventory automatically?
• What does it cost to leave? Some 3PLs charge per-pallet exit fees that can run into thousands.

Negotiate a pilot of 30 to 90 days before committing to a long contract. The proof is in the first month of real operations, not the sales pitch.

When to add an ERP or inventory platform

Shopify’s built-in inventory is excellent for stores up to maybe 500 SKUs across a few locations. Above that, or when you start dealing with manufacturing, wholesale, or B2B orders alongside DTC, you outgrow it. The two most common upgrade paths for Australian Shopify merchants:

• Cin7 Core (formerly DEAR Systems): Auckland-built, strong in Australia and NZ, handles purchase orders, manufacturing BOMs, multi-warehouse, B2B portal. Around AUD 350 to 1,000 per month depending on tier.
• QuickBooks Commerce (formerly TradeGecko): now wound down for new customers but still in use by some Australian merchants. If you’re on it, plan a migration.
• Cin7 Omni (the larger product): for merchants with EDI, multi-channel retail (Shopify plus Amazon plus eBay plus wholesale), and complex compliance needs.
• NetSuite or Microsoft Business Central: full ERP territory. Right when your business has finance complexity beyond what Xero can handle, typically $20m+ revenue.

The signal that you’ve outgrown Shopify-native inventory: you’re reconciling stock manually in spreadsheets, or you’re running a wholesale B2B operation alongside DTC and the two are stepping on each other. Those are ERP problems.

Forecasting: simple models beat fancy ones

Most Australian Shopify merchants don’t need machine learning forecasting. They need a clear-eyed look at trailing 90-day sales velocity, a manual adjustment for known seasonality (Black Friday, Christmas, EOFY), and a buffer for lead time variability. A spreadsheet works for the first $5 million in revenue.

The forecasting tools that actually help are the ones that surface the right data, not the ones that promise AI-driven predictions. Inventory Planner and Stocky both do this well. The output you want is a weekly recommended purchase order list, sorted by urgency, with reasoning you can sanity-check.

Bundles and kits: where inventory gets tricky

If you sell bundles (multiple SKUs sold together as one product), inventory accounting gets complicated. Selling one bundle should decrement each component SKU. Shopify handles this through Bundles app or through third-party tools like Bundle Builder. We’ve written more about that in our bundle and mix-and-match builder guide. The key is to make sure your bundle inventory display reflects the constraint of the lowest-stock component, not a fictional bundle stock count.

Audit your stack quarterly

Inventory app sprawl is real. We’ve audited stores running an inventory tool, a separate bundling tool, a separate purchase order tool, a separate forecasting tool, and a 3PL connector, all paying monthly fees and overlapping in functionality. Once a quarter, list every app touching inventory and ask whether each one is still earning its place. Our Shopify app audit guide covers the methodology.

Operational discipline beats software

The Australian Shopify merchants we’ve seen handle inventory best aren’t the ones with the fanciest tools. They’re the ones with a weekly reorder review, clear ownership of who places purchase orders, and a 3PL relationship managed like the business-critical partnership it is. Software accelerates good operations. It can’t replace them.

If you’d like a hand setting up your inventory workflows, integrating a 3PL, or scoping an ERP upgrade, our Sydney development team has worked through these projects for dozens of Australian merchants. Start a project to scope yours, and have a look at our support retainer if you’d like ongoing help keeping things running.