Once you run more than one warehouse, you’ll inevitably hit the case where a single order ships from multiple warehouses. To the customer it’s one order, but behind the scenes two items might be pulled from your Tokyo warehouse and one from Osaka. That’s split fulfillment.
On top of that, partial fulfillment — sending some items now and the rest once they arrive — happens all the time. This article focuses on the order-handling mechanics: how inventory moves during split and partial fulfillment, and which location’s numbers your Google Sheet should treat as the truth.
When one order ships from multiple warehouses
In Shopify, the place where a product stocks inventory is called a location. If you give each warehouse its own location, inventory is recorded per location. When a customer orders several items at once, they aren’t necessarily all in one warehouse. It’s common for one item to be in Tokyo and another only in Osaka.
In that case the order decides, item by item, where each one ships from, and ends up dispatching from multiple warehouses. On the Shopify order screen this appears as several fulfillments (units of shipment). One order does not always mean one location — understanding that is the first step of multi-location operations.
How inventory is allocated during a split shipment
When an order comes in, inventory first moves to a state called committed. It hasn’t shipped yet, but it’s set aside for this order. For an order that spans multiple warehouses, this commitment is split per location.
- 01At order time, each item is assigned a location to draw from (e.g., item A from Tokyo, item B from Osaka)
- 02The relevant quantity becomes committed at each location, and available drops by that amount
- 03When a warehouse actually ships, that location’s on-hand quantity decreases
- 04Once every item has shipped, the whole order is marked fulfilled
The key point is that the timing and place where stock drops differ per location. If Tokyo ships first, Tokyo’s on-hand falls first, while Osaka stays committed until it ships. If you view the order as one lump, it’s easy to miss this per-location offset.
Where the remaining items’ stock sits during partial fulfillment
With partial fulfillment, you might ship two of three ordered items from Tokyo now and leave the last one waiting for Osaka to restock. The two shipped come off Tokyo’s on-hand, while the unshipped item stays committed in Osaka. In other words, the remaining item’s stock waits, reserved at the location it was assigned to.
Where sheet sync and split shipments tend to clash
Here’s the heart of it. If you run Google Sheets as your inventory source of truth and write quantities into Shopify, split fulfillment and sheet sync can collide. The biggest trap is ambiguity over which state of inventory the sheet represents.
As a rule, what the sheet should hold is each location’s on-hand quantity. Available is a figure Shopify calculates automatically as orders come and go, so overwriting it from the sheet causes double subtraction against committed orders and throws the numbers off. Keep the sheet defined as how many units physically sit in each warehouse, and you stay safe.
- Decide that the sheet’s quantity column represents on-hand per location
- Don’t write available directly from the sheet (it double-counts against commitments)
- For a location mid-shipment, align the sheet update with the warehouse’s stock count
- For products that move across several locations in a split, keep a trail of which warehouse’s row you updated
Operating rules that assume split fulfillment
You can’t simply avoid split fulfillment, so the realistic move is to set rules that assume it happens. Prepare simple agreements that won’t confuse even new warehouse staff.
First, hold the sheet as one row per location-and-SKU pair, so it’s obvious which warehouse’s stock you’re editing. With an app that supports multiple locations — such as Sync Master — you can map each location column in the sheet to its matching Shopify location and reflect per-warehouse on-hand directly. Run a connection test before the real sync to validate your column mapping and avoid the accident of writing into the wrong warehouse.
Don’t assume one order means one place. In multi-location operations, an order is best seen as a transaction that draws a little stock from several places.
Preventing over- and double-deduction
Finally, the scariest accident in multi-location split shipping: double-deducting stock. It happens when you manually subtract and write down the inventory that Shopify already reduced automatically through the order. Shopify subtracts once, the sheet sync subtracts again, and you lose the quantity twice.
- 01Put only count-based on-hand into the sheet, and don’t hand-subtract for orders
- 02Update only locations that have finished shipping, and leave still-committed locations untouched
- 03Schedule automatic sync for hours when warehouse inbound and outbound activity is calm
- 04Always confirm the target location before updating, checking you’re not overwriting another warehouse’s row
Split and partial fulfillment are unavoidable mechanics for any shop with multiple warehouses. But hold on to three ideas — the sheet represents on-hand, committed and on-hand are different, and you update only locations that have shipped — and number drift drops sharply. Try building the habit of seeing an order as a collection of places into your operating rules.