Multi-Location Inventory Tracking for FBA Sellers | Inventory Hero
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Multi-Location Inventory Tracking for FBA Sellers
Multi-location inventory tracking for FBA: what to track across FBA, AWD, and a 3PL, why total position drives reordering, and how to keep it accurate.
How do I track inventory across multiple locations?
Record on-hand quantity per location (FBA, AWD, a 3PL, your own warehouse), plus units in transit between them, for each SKU. Then roll those up into a total owned and a total sellable position. Your reordering runs on the total, while your fulfillment planning uses the per-location detail. Whether you use a spreadsheet or a system, the requirement is one current, rolled-up view.
Why does multi-location tracking matter for reordering?
Because reordering off one location's number leads to mistakes. If you look only at your FBA quantity and forget the stock sitting in a 3PL or AWD, you double-order and create excess; if you forget units in transit, you may over-order to cover a gap that is already being filled. Accurate reordering needs your total position across every location and everything in transit.
Andrew Erickson is the founder of Inventory Hero. He has spent years working with Amazon FBA sellers on demand forecasting, restock planning, and the cash flow side of running a private-label brand. Inventory Hero exists because every spreadsheet-based inventory system he tried eventually broke — usually right before Q4.
Should I use a spreadsheet or software for multi-location inventory?
A spreadsheet is fine for one or two locations and a small catalog. It breaks down as locations and SKUs multiply, because nobody updates it the moment stock moves, so it drifts out of date exactly when you rely on it. A system that syncs each location and rolls up the total removes the manual upkeep and keeps the position current, which is what accurate reordering needs.
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Multi-location inventory tracking becomes a real problem once your inventory lives in more than one place: FBA, AWD, a 3PL, your own warehouse, and in transit between them, and getting it wrong costs you in over- and under-ordering. The short version: your reorder math has to run on total position across every location, not on any single one, and the common failure is reordering off your FBA number alone. Below is what to track, why the total matters, and how to keep it accurate.
The difficulty is not any one location; it is that they scatter your inventory across systems that do not naturally talk to each other:
FBA shows its own quantity in Seller Central.
AWD shows its quantity in its own view.
A 3PL reports through its portal or a file.
Your own warehouse and in-transit stock live wherever you record them, often a spreadsheet.
No single screen shows the truth, so you have to assemble it, and the assembling is exactly where errors and staleness creep in. The more nodes and SKUs, the harder it gets.
For each SKU, you need a small set of numbers that roll up cleanly:
On-hand per location. How many units are physically sellable-or-storable at FBA, AWD, the 3PL, and your own warehouse.
In transit. Units that have physically left their origin and are moving between locations (supplier to 3PL, 3PL to FBA, AWD to FBA): owned, but not yet available where they are headed. Units you have ordered but the supplier has not shipped are an open PO, not in transit; track those separately so you do not count stock that has not left the factory.
Total owned. The sum of everything above, the real quantity you have paid for.
Total sellable now. What can actually ship to a customer today, which is usually the FBA (and own-channel) portion, not the bulk sitting upstream.
The distinction between total owned and total sellable is the one that trips sellers up: you own a lot, but only some of it can ship right now, and both numbers matter for different decisions.
Your reorder decision depends on the total, but the timing depends on the detail:
Reorder off total owned plus in transit. If you have 300 units in a 3PL and 100 in FBA, you have 400, not 100; reordering as if you had 100 creates excess.
Time replenishment off the sellable position and the lead time between nodes. Stock in AWD or a 3PL still takes days to reach FBA and become sellable, so factor that leg into your days of supply and reorder date.
Watch for the double-count and the blind spot. Counting the same in-transit units twice, or forgetting a node entirely, both throw off the total. Accuracy across locations is what keeps the reorder right.
Worked through, the mistake is stark. A SKU sells 10 units a day. FBA shows 120 units, so 12 days of cover, and your reorder trigger is 30 days, so FBA alone screams "reorder now." But a 3PL is holding 600 units of it, and 300 more are on the water. Your true position is 1,020 units, over 100 days of cover. Reorder on the FBA number and you pile a fresh order on top of 900 units you already own, manufacturing months of excess. The correct move was to transfer from the 3PL into FBA, not to buy more. That single error, repeated across a catalog, is how multi-location sellers end up cash-poor and overstocked at once.
Get the total right and your reordering stops swinging between over- and under-buying.
Multi-location tracking is only useful if it is current, which is where it usually fails:
Update on movement, not on memory. The position drifts the moment stock moves and nobody records it, so tie updates to the movement (a shipment created, a transfer confirmed).
Reconcile per location. Each node can develop its own discrepancy; reconciling per location keeps small errors from compounding into a wrong total. See inventory accuracy.
Roll up in one place. Whatever tools you use, the numbers have to converge into a single current total, or you are back to guessing.
A spreadsheet handles one or two locations and a small catalog. It breaks down as nodes and SKUs multiply:
It goes stale. Nobody updates every location the moment stock moves, so the rolled-up total is wrong exactly when you need it.
It does not sync. Each location's real numbers live elsewhere, so the sheet is a manual copy that lags reality.
It hides the total. Without automatic roll-up, the number that drives reordering is the one most likely to be out of date.
If you are on a spreadsheet today and not ready to buy software, a workable interim structure is one row per SKU with columns for FBA, AWD, 3PL, and in-transit, a total-owned formula and a total-sellable formula that add the right columns, and a date-last-updated column to force the discipline of updating on movement. Refresh it on a set cadence (pull FBA from Seller Central, AWD from its view, and your 3PL from its portal) rather than by memory. It will still go stale between refreshes, which is the ceiling a spreadsheet hits.
A system that syncs each location and computes the total removes that manual upkeep and keeps the position live, which is what multi-location reordering actually requires at scale.
Multi-location inventory tracking is the discipline of maintaining one true, current position across FBA, AWD, a 3PL, your own warehouse, and everything in transit. Track on-hand per location and in transit, roll it into total owned and total sellable, reorder off the total, and keep it accurate by updating on movement and reconciling per node. The failure to avoid is reordering off FBA alone. For how the extra nodes fit, see when to use a 3PL and Amazon AWD; for the wider system, restock planning.