You send 200 units to Amazon. A week later, Seller Central shows your SKU has "220 in inventory" — but only 40 are actually available to sell. No units are lost, nothing's wrong, and nobody made a mistake. This is just how FBA inventory statuses work — and understanding them is the difference between panicking over a false alarm and knowing exactly what's happening to your stock at any moment.
The Short Version
Every unit you send to Amazon sits in exactly one status at a time, and that status determines whether it's sellable, whether it counts toward Prime delivery, and whether you can pull it back. Following the actual path a unit takes: it starts Inbound (Working → Shipped → Receiving), then becomes On-hand — Amazon's own term for Available plus FC-Transfer combined — and from there can move into Reserved, or if something's wrong, Unfulfillable or Researching. Reserved and Inbound each split further into sub-statuses that behave differently — which is where most of the confusion (and most of the "why isn't this selling" support tickets) comes from.
The Core Statuses
1. Inbound
The process starts with you sending your FBA inventory to Amazon via Seller Central. From the point of creating the shipment to the unit being received by Amazon, it moves through three sequential stages while being in the "Inbound" status:
- Working — the shipment plan exists in Seller Central, but nothing has shipped yet.
- Shipped — the carrier has picked up the shipment; tracking is attached. Per Amazon's own definitions, this bucket actually covers four physical sub-stages — Shipped, In-transit, Delivered, and Checked-in — all grouped under one "Shipped" status for inventory purposes.[1]
- Receiving — Amazon has started checking units in from this specific shipment. Once units are checked-in and received, they move out of the Inbound state and into Available or FC-Transfer.
2. Available
The unit has been checked in, passed condition checks, and is live for customer orders — Amazon defines this as the number of customer-buyable units currently in fulfillment centers, ready to fulfill orders, calculated in real time, not including units pending removal or buyable units in transit. This is the only status where a unit is unconditionally ready to sell today. (Note: older tools, reports, and some Amazon documentation may still use the term Fulfillable for this same status — afn-fulfillable-quantity in the Manage FBA Inventory report is the same thing as "Available.")
3. FC-Transfer
FC-Transfer refers to units physically moving from one fulfillment center (or a receive center) to another to place inventory closer to customers. These units are sellable — customers can find and buy them, but they might be shown a future ship date. Transfers typically take 1–25 days, longer if delayed by weather or other factors.[1] It sits alongside Available in Amazon's own formula — On-hand = Available + FC-Transfer.
4. Reserved
"Reserved" is the status most sellers misread as a single problem. In fact, it's three distinct situations, each with a different cause and a different resolution path:[1]
- Customer Order — units tied to a placed order, held until they ship. Releases automatically once the order ships, or returns to sellable if the customer cancels first. No action required from the seller.
- FC Processing — units set aside for additional processing: verification of item dimensions and weight, pending investigations, or pending removal orders. Amazon notifies you if any action is required.
- Staging — units Amazon is deliberately holding back inside the fulfillment center, released into your sellable count as your current Available stock depletes. Amazon's own tooltip on this status reads: "Units temporarily held by Amazon to ensure optimal fulfillment speed. No action by you is required." This is a pacing mechanism, and the units stay Prime-eligible the entire time.
5. Unfulfillable
The unit can't be sold — usually because of damage discovered at the warehouse, an expired condition, or a customer-return defect. Amazon notifies you when this happens, and if it's not addressed within 30 days, Amazon disposes of the unit.
6. Researching
Units Amazon is actively investigating — typically tied to a lost-or-damaged claim working toward reimbursement or resolution. Units will never remain in Researching status for more than 60 days.[1]
The Full Status Flow, Visualized
The diagram below follows the actual path a unit takes: Inbound first, then the fork into Available or FC-Transfer, then into Reserved and its sub-types, with the problem paths (damage, disposal, investigation) branching off in red and amber. Teal shows the standard, sellable path.
Worked Example
The above status definitions and status switch triggers can be quite confusing, especially for newer FBA sellers. To help us understand these better, let's work through an example. Let's say sample SKU WIDGET-4471 has 354 units somewhere in the FBA system on a given day, spread across every stage above, listed in the order a unit actually moves through them:
| Status | Units | What's happening |
|---|---|---|
| Inbound — Working | 0 | No shipment plan currently open |
| Inbound — Shipped | 60 | New shipment in transit, no units received yet |
| Inbound — Receiving | 20 | A second, older shipment where check-in has started |
| Available | 210 | Live and sellable right now |
| FC-Transfer | 25 | Being redistributed to different FCs for better regional coverage |
| Reserved — Customer Order | 12 | Sold in the last few hours, awaiting ship confirmation |
| Reserved — FC Processing | 8 | Pulled for a routine dimension/weight audit |
| Reserved — Staging | 14 | Held back for release pacing, Prime-eligible, no action needed |
| Unfulfillable | 5 | Damaged in a prior shipment, 30-day clock running |
At a glance, "354 units" tells you almost nothing useful. The breakdown tells you: 210 are available for customers and ready to ship today, 25 are FC-Transfer — still buyable, but possibly showing a later ship date, 20 are Reserved (Customer Order + FC Processing) and will self-resolve within days, 14 are Staging — Prime-eligible and needing no attention at all, 5 need a decision before day 30, and 80 are still on their way in — split across two shipments in different stages.
Buyable vs. Prime-Eligible: Why the Same Listing Can Look Different by ZIP Code
This is the nuance that catches even experienced sellers off guard, because it doesn't behave the way most other e-commerce inventory logic works.
Buyable status is network-wide. The Prime badge is not.
If a unit exists anywhere in a sellable status — Available or FC-Transfer — the Buy Box is active for every shopper, everywhere, regardless of which fulfillment center that unit physically sits in. Amazon doesn't hide the listing from distant shoppers. Amazon goes a step further here too: a listing can still show as buyable even at zero Available quantity, since Amazon anticipates the seller replenishing — buyable is not strictly gated on a positive on-hand count (more on this later).
The Prime badge is different. It only displays if Amazon estimates that specific shopper, from their specific ZIP code, will receive the item within Amazon's fast-delivery window.[2] One seller's real-world example: with all inventory sitting at a single East Coast FC, shoppers browsing from Florida saw the Prime badge, while shoppers browsing from California — a longer delivery estimate — did not, on the exact same listing at the exact same moment.[2]
Why this happens
Amazon distributes inventory across multiple fulfillment centers nationwide once stock levels justify it, which is what produces fast delivery — and Prime badge visibility — across most regions. A new SKU, or one with thin inventory, often lands at only one or two FCs at first. That's exactly when sellers see the "Prime shows for some shoppers, not others" pattern. It resolves itself as inventory naturally spreads across the network with volume and reorder cycles — or can be influenced sooner through Amazon's inbound placement options at shipment creation. How you route inbound shipments has a direct, and often overlooked, effect on this: see our companion piece on Amazon's Inbound Placement Fee for how minimal-split vs. Amazon-optimized-split shipping decisions affect both cost and how quickly your inventory ends up spread across regions.
Freshly-received inventory has a short lag before Prime shows anywhere
Recently checked-in inventory won't display the Prime badge until Amazon's delivery-estimate system has fully processed it — a unit can be technically Available and still not show Prime for a brief window while that catches up.[2]
FC-Transfer units: buyable, but not Prime yet
Units in FC-Transfer status are still sellable, but may show a future ship date rather than a standard fast Prime estimate until they land at the destination FC, over a typical 1–25 day window.[1] "Buyable" and "Prime-eligible" are not the same guarantee.
Technical Reference: Reading the Manage FBA Inventory Report
Everything above is what you see on the standard Manage Inventory dashboard. If you want the Working / Shipped / Receiving breakdown, or the FC-Transfer count as its own number, you need the downloadable FBA Inventory report, or the equivalent SP-API endpoint.[3] The dashboard's expandable detail view stops at a single lumped "Inbound" figure — it doesn't break out the three sub-stages.
Field reference
| Field | What it means |
|---|---|
afn-fulfillable-quantity | Available (Amazon's older field name for this same status) |
afn-unsellable-quantity | Unfulfillable units |
afn-reserved-quantity | Reserved — Customer Order + FC Processing + Staging |
afn-fc-transfer-quantity | Units specifically in FC-to-FC transit |
afn-researching-quantity | Units under investigation |
afn-inbound-working-quantity | Notified, not yet shipped |
afn-inbound-shipped-quantity | Tracking attached, no units in that shipment received yet |
afn-inbound-receiving-quantity | Un-received units in a shipment where receiving has started |
afn-warehouse-quantity | Total on-hand — see formula below |
afn-total-quantity | On-hand + all inbound stages |
afn-onhand-buyable-quantity | What a customer can actually purchase right now |
afn-future-supply-buyable | Units made purchasable early via In-Stock Head Start, before physical receipt |
afn-reserved-future-supply | Units already sold against that future supply |
Formulas
These formulas aren't spelled out anywhere in Amazon's field documentation as equations, but they follow directly from Amazon's own status definitions in the primary reference for this article:[1]
afn-warehouse-quantity = fulfillable + unsellable + reserved + fc-transfer + researching
afn-total-quantity = warehouse-quantity + inbound-working + inbound-shipped + inbound-receiving
afn-onhand-buyable-quantity = fulfillable + fc-transferIn-Stock Head Start Program
This is a separate, opt-in-eligible program that lets temporarily out-of-stock listings stay active and buyable while replacement inventory is still in transit — provided Amazon has reliable ETA data, typically from a carrier with a standing FC appointment.[4] It surfaces in the "future supply" fields above and doesn't show up anywhere on the standard dashboard.
What to Actually Watch Day to Day
- Reserved climbing while Available drops — check whether it's Customer Order (normal, self-resolving) or FC Processing (worth monitoring if it exceeds ~7–10 days). Staging needs no attention at all.
- Inbound "stuck" — remember Shipped-vs-Receiving isn't about physical location once partial receiving starts. Don't panic over a shipment showing Receiving with low counts; check the shipment reconciliation tab, not just the SKU-level inventory number.
- Prime badge inconsistency reports from customers — before assuming something's broken, check how many FCs your inventory is actually distributed across. Thin, single-FC stock is the most common cause.
Once you know this map, "220 units in inventory, only 40 sellable" stops being a red flag and becomes a five-second read: some are Reserved, some are still Inbound, some are in FC-Transfer — and none of it means something's broken. That's the whole point of learning the statuses: less time firefighting phantom problems, more time on the ones that actually need you.
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- Amazon Seller Central, FBA Inventory page — "Column and metric definitions." Primary reference for this article, accessed via Seller Central. https://sellercentral.amazon.com/help/hub/reference/GTMXYZN64UJL7TT6
- Amazon Seller Central Forums, "Prime badge not showing" — sellercentral.amazon.com
- Amazon Selling Partner API, FBA Reports reference — developer-docs.amazon.com
- Amazon Seller Central Help, "In-Stock Head Start" — sellercentral.amazon.com.au