How to Send Inventory to Amazon FBA (And What Goes Wrong)

What 'Send to Amazon' Actually Covers

Send to Amazon isn't one button — it's a sequence of decisions inside Seller Central that Amazon groups under a single workflow name. You build a shipping plan (which SKUs, how many units, shipped from where), tell Amazon how the units are prepped, assign labels, choose a carrier, and confirm the fulfillment center(s) the units are going to. Only after all of that does a truck actually move.

"Send to FBA," "send shipment to Amazon FBA," and "send inventory to Amazon FBA" all describe the same screen. It sits after registering for FBA and listing a product, and before Amazon starts picking and packing orders on your behalf.

One decision that surprises new sellers: Amazon's placement algorithm, not you, usually decides whether a shipment lands in one fulfillment center or gets split across several. You can pay for single-location placement instead, but that's a trade-off — lower complexity on your end, a fee for it, and a shipping cost difference depending on where your demand actually is.

A Worked Example: What a Shipment Actually Costs to Move

Say you're sending 500 units of one SKU, each a 10x8x4 inch box weighing 1.2 lbs packaged. The shipping plan splits into two fulfillment centers because that's where Amazon's placement model wants the inventory, not because you asked for it.

Three separate cost meters start at different moments. Freight in starts the second you hand units to the carrier. Fulfillment fees don't touch you until a unit actually sells, and they're set by size tier and weight, not by what you paid for the product. Storage starts the day the unit is checked in as received — whether it sells that week or sits for six months.

The numbers above are illustrative, not a quote. Amazon revises size-tier and dimensional-weight bands often enough that a figure from last quarter can be wrong today, and its own Revenue Calculator is the only place to get the real fulfillment and storage fee for a specific ASIN. What doesn't change is the structure: three clocks, three different start dates, and a shipment plan that decides how big the first one is before the other two even start.

The Common Mistakes That Turn a Shipment Into a Problem

FNSKU mismatch. If the barcode on the unit doesn't match what the shipping plan expects — manufacturer barcode instead of FNSKU, or relabeled after the plan was built — receiving stalls and units sit in an unfulfillable status while a support case works its way through the queue.

Prep category errors. Poly bagging, bundling, and suffocation-warning rules are set at the category level, not guessed at per shipment. Getting this wrong doesn't just risk a rejected case — it can trigger a prep-fee chargeback for every unit Amazon has to fix on your behalf.

Shipping the round number instead of the right number. The workflow makes it easy to send a full pallet or a full container because that's the tidy quantity, not because sell-through calls for it. Overship a slow SKU and the aged-inventory clock is already running before you've sold through half of it.

We've watched this exact pattern across the 70+ brands live inside the Full Circle and reMKTR group right now: the shipment plan is built correctly, unit by unit, but the reorder number behind it is three weeks stale — set off a sales velocity that changed after a price move or a listing update. It's a mistake we've made ourselves: signing off on a shipment sized to match the forecast the day the plan was built, not the forecast on the day the truck actually left.

When the Shipment Doesn't Match What You Sent

Sometimes the count Amazon confirms received doesn't match what left your dock. That happens for real reasons — a case gets damaged in transit, a carrier miscounts at drop-off, a unit gets misreceived into someone else's shipment — and Amazon runs a claims window for it, not an argument.

Pull the shipment confirmation and the carrier's proof of delivery first. If the carrier's paperwork shows the full count arrived and Amazon's receiving report shows fewer, that's a reimbursement claim, not a shrug — file it inside the window. Past the window, the missing units are gone on paper even when you can prove they weren't gone in fact.

If the shipment arrived complete, was received on time, and the SKU still isn't selling — that's not a shipment problem. The units are on the shelf and findable. That's usually a listing, price, or ad account issue, and it's worth routing to whoever runs your PPC before touching the supply chain side again. If that's not you, that's Dr. PPC's job, not ours.

The Shipment Is the Easy Part

Getting a shipment plan built and units moving is a one-day task once you know the workflow. What separates a healthy FBA operation from one quietly bleeding money is everything upstream and downstream of that shipment: the reorder timing that decided how many units to send, the storage clock that started the moment they were received, and whether a discrepancy claim got filed inside the window or missed entirely.

Dr. Stock — run by Fable 5, from Full Circle, which has managed more than $500M in revenue across 100+ brands — works that layer: reorder timing, aged-inventory and storage-fee disputes, FBA fee and dimensional-weight errors, and shipment discrepancy recovery, with purchasing decisions always routed to a human regardless of autonomy setting. It's not a fit if you need someone to physically pick, pack, or store your inventory — that's what FBA (or a 3PL, if you're off-Amazon) already does.