FBA Warehouse Codes: What the Four Characters Decide

Four characters decide which port your container should sail into, which rail ramp it should leave from, and how many truck trips you will pay for at the other end. They do not tell you where to send the truck.

That gap is where most FBA freight mistakes start. A seller reads ONT8, searches for it, finds a street address on a third-party list, and sends a container there. Six weeks later the inventory is in a returns pile in another state, and the invoice has a redelivery charge on it.

This page separates the two things the code is used for: planning freight, and addressing freight. One of them you can do from a list. The other you can only do from Seller Central.

What the four characters encode

Amazon states the rule plainly: the first three characters of a fulfillment center code come from the IATA airport code of the closest large airport. The remaining characters distinguish individual buildings in that same metropolitan area.

So LAX9, ONT8 and PHX6 are not arbitrary strings. They anchor a facility to a metro, and a metro anchors to a port and a rail ramp. That is the whole value of the code in a freight plan: it turns a warehouse name into a lane.

Policy source: Amazon Seller Central, Amazon fulfillment centers in the US (G201811680), checked 5 November 2026.

Two consequences follow, and both matter more than the lookup itself:

• A code is not stable across time. Amazon adds, closes and reassigns buildings. Any list you downloaded last year, and any list a supplier keeps on a shared drive, describes a network that has already moved.
• A code is not an address. The list gives you a city. The street address, the receiving hours and the appointment rules come from your own shipment plan, for your own shipment ID.

Reading a code into a freight plan

The table below is the part of a code lookup that survives all the changes: metro to ocean gate. Use it to choose a port of discharge and to estimate whether your freight moves by truck or by rail. Do not use it as an address book.

Read a plan against this table and the shape of the shipment usually appears. Three cartons to ONT8 and one to ABE is not one delivery; it is a West Coast dray plus a transcontinental move, and the second leg is not priced like the first.

If you want the facility-level view, including which buildings sit in which metro and how far they are from a given address, use the US FBA warehouse codes and addresses lookup. It is built for the planning question, not for the addressing question.

Three kinds of building appear in the same list

Not every four-character code is a fulfillment center that receives inventory directly. The list mixes building types, and treating them as interchangeable is a common cause of a truck arriving somewhere it cannot unload.

None of this is visible from the code alone. The code tells you the metro; the shipment plan tells you the type.

Why you cannot pick the warehouse

Amazon assigns inbound locations. At the end of the Send to Amazon workflow you choose how much you are willing to split, and the system returns one or several destinations. You do not get to say "I want ONT8 because my factory ships from Shenzhen".

What you can choose is how many places you send to, and that choice is priced. Since 15 January 2026 the inbound placement service fee uses these options:

The fee is charged 45 days after the shipment is received, based on quantities actually received and on the inbound location. It is not shown at the moment you confirm, which is why sellers price a shipment on freight alone and discover the placement cost two months later.

Policy source: Amazon Seller Central, FBA inbound placement service fee (GC3Q44PBK8BXQW3Z), 2026 rate card effective 15 January 2026, checked 5 November 2026.

The arithmetic that matters: one destination is the cheapest freight and the most expensive placement. Five destinations invert both. The only way to answer it is to quote the freight for each option and add the placement fee, which is exactly what the China to USA freight rates calculator is for.

Where the code has to appear, and where it must not

The duplication is deliberate. Amazon's own carrier rules require the carrier to state that the freight is for Fulfillment by Amazon and to quote the FBA shipment ID when booking, because the dock matches the truck to a shipment, not to a company name.

Five mistakes that look like lookup mistakes

Most "the code was wrong" incidents are not lookup failures. They are one of these:

• Sending to a list address. The city is right, the street is stale, or the building now handles a different type of inventory. The only address that counts is the one in your confirmed plan.
• Reusing labels after a split. Amazon changed the destinations; the cartons still carry the old shipment IDs. The receiving dock now has freight it did not expect.
• Treating an IXD as the final warehouse. It is a cross-dock. Freight booked with the wrong appointment type waits.
• Quoting one destination for a plan that splits. Four destinations means four delivery legs, four appointments and four sets of accessorials.
• Ignoring the appointment. A correct address with no appointment is still a truck that gets turned away. Amazon requires carriers to book at least 24 hours ahead and allows three appointment requests per shipment or trailer.

Policy source: Amazon Seller Central, Carrier requirements for delivering shipments (G200978420), checked 5 November 2026.

How to look up a code without trusting the list

1. Get the code from Seller Central, after the plan is confirmed. Not from a supplier, not from a chat group.
2. Map the code to a metro, and the metro to a port. That decides the ocean leg. The FBA warehouse code and address lookup shows the metro, the distance to a given city or ZIP, and the buildings in that area.
3. Count the destinations before you price anything. One, three or five changes both the freight and the placement fee.
4. Quote the real delivery addresses from the plan, and check the appointment lead time for that facility.
5. Re-check after any plan change. A split added on a Friday invalidates labels printed on Thursday.

Questions sellers ask about FBA warehouse codes

Can I ask Amazon for a specific fulfillment center?

No. Inbound placement is assigned by Amazon's system based on the products, quantities, your spread of inventory and center capacity. What you control is the number of destinations you accept, and that is a fee decision rather than a location decision.

Does the number at the end mean anything?

It identifies the individual building within the metro. LAX9 and ONT8 are different addresses in the same freight market; the number does not encode size, category or capability.

Why does my code not appear on any list?

Because lists lag. New buildings appear before third-party directories update, and closed buildings stay listed for months. The plan in Seller Central is the authority; a list is a planning aid.

Is the address on a public warehouse list safe to ship to?

No. The street address must come from your confirmed shipment plan, because the dock matches the truck to a shipment ID. Freight arriving at a correct address without a matching shipment can be refused.

What does a wrong warehouse cost?

Three separate bills: the carrier's redelivery or detention, a new appointment and possibly a second drayage leg, and Amazon's handling of freight that does not match the plan. The full breakdown is in our guide to FBA shipments that arrive at the wrong warehouse.

Sources

All sources checked 5 November 2026. Warehouse networks, fees and appointment rules change; the checked date is part of the citation, not decoration.