Amazon FBA Inventory Management

Manage owned stock and Amazon FBA inventory as one picture: prep-warehouse counts, shipment tracking, and reconciling what Amazon reports against what you actually sent.

Amazon FBA Inventory Management

By Tibeau De Grauwe, FounderUpdated August 2026

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Why FBA sellers are really running two inventories

Once inventory leaves your prep warehouse and enters Amazon's fulfillment network, you lose direct visibility into it—you rely on Amazon's own reports for received quantity, sellable stock, and reserved units. That is a different number from what you know you packed and shipped, and the two do not always match.

Short shipments, mis-picked cartons at receiving, and inbound damage all show up as a gap between what you sent and what Amazon says it received. Without your own prep-side record, that gap is invisible until a reconciliation shows you sold more or less than you thought you had.

What to track before stock leaves your warehouse

Track quantities at the box or carton level as you prep an FBA shipment, not just a single SKU total—this is what lets you catch a short shipment or a mis-packed carton before it becomes a mismatch with Amazon's receiving report. Keep the shipment plan, carton contents, and ship date recorded against each SKU so you have something concrete to reconcile against once Amazon confirms receipt.

For sellers also holding stock outside FBA—for wholesale, a storefront, or other marketplaces—track that owned inventory separately from what has already shipped to Amazon, so a popular SKU sold at a busy time doesn't look available when it has already left for a fulfillment center.

  • Record carton/box-level contents at prep, not just a SKU total
  • Log shipment plan ID, ship date, and quantity per SKU
  • Keep owned stock separate from stock already sent to FBA
  • Reconcile Amazon's received-quantity report against your prep records

Selling on Amazon alongside other channels

Most FBA sellers are not Amazon-only—the same SKU often also sells through a Shopify storefront, wholesale, or another marketplace. Keeping one shared stock record for owned inventory (before it splits into what is sent to FBA vs. held for other channels) is what prevents overselling a channel that is drawing from a pool that already looks emptier than the accounting shows.

StockFlow tracks that owned-inventory side—receiving, prep, and what has shipped where—so FBA is one destination among several your stock flows to, rather than a separate system you reconcile by hand.

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Frequently asked questions

Does StockFlow track inventory inside Amazon FBA warehouses directly?
StockFlow tracks your owned inventory—what is in your prep warehouse and what you have shipped to FBA—so you have your own record to reconcile against Amazon's received-quantity and sellable-stock reports, rather than relying on Amazon's numbers alone.
Why does Amazon's received quantity sometimes not match what I shipped?
Short shipments, receiving errors at the fulfillment center, and inbound damage are the most common causes. Tracking carton-level contents and ship dates on your side gives you something concrete to compare against Amazon's inbound shipment report when a mismatch shows up.
How do I manage inventory for Amazon FBA plus my own store?
Keep one shared stock record for owned inventory before it splits by destination, so selling through your storefront and shipping to FBA both draw from the same accurate total instead of two disconnected counts.
What should I track before sending an FBA shipment?
Record quantities at the box or carton level (not just a SKU total), plus the shipment plan ID and ship date per SKU. That level of detail is what lets you spot a short shipment or mis-pack before it becomes an unexplained stock gap later.