what is amazon fba

How Amazon FBA Works

The Amazon FBA meaning is literal: Fulfillment by Amazon, where Amazon does the fulfilling. It's a service you buy as a third-party seller, not a business model of its own, and it sits inside Seller Central, the self-serve platform where you own your listings, set your prices, and get paid a settlement every couple of weeks. That's worth naming because of the Amazon Vendor Central vs Seller Central distinction that confuses newcomers: Vendor Central is the invitation-only wholesale relationship where Amazon buys your goods and resells them as first-party retail, so you're a supplier with purchase orders and payment terms rather than a merchant with settlements. FBA is a Seller Central thing. If you're reading this, you're almost certainly a Seller Central seller.

With FBA, you ship your products in bulk to one or more Amazon fulfillment centers instead of shipping directly to customers. When a customer orders, Amazon's warehouse staff pick, pack, and ship the item, and Amazon's customer service team handles returns and basic support. You keep ownership of the inventory until it sells, but you no longer touch the box.

In exchange, Amazon charges fulfillment fees (per unit, based on size and weight) and storage fees (based on volume and time of year, with higher rates heading into peak season). There are also potential long-term storage surcharges for inventory that sits too long. The exact fee schedule changes periodically, so always verify current rates against Amazon's published fee schedule rather than relying on numbers you saw last year.

FBA is a major reason third-party sellers have become such a dominant force on the platform. Third-party sellers now account for more than half of the physical gross merchandise sold on Amazon, and FBA is the fulfillment method most of them rely on to compete for the Buy Box and Prime eligibility.

The step-by-step flow looks like this in practice. You create a shipping plan in Seller Central listing which SKUs and how many units you're sending. Amazon assigns you one or more destination fulfillment centers, sometimes splitting a single shipment across several. You prep and label each unit to Amazon's requirements (poly bags, suffocation warnings, FNSKU barcodes over the manufacturer barcode where required), apply the Amazon FBA box labels the shipping plan generates for each carton, book freight or use Amazon's partnered carrier program, and ship. Plenty of sellers never do this themselves: a prep center for Amazon FBA will receive goods straight from your supplier, inspect, poly-bag, label, and forward them to the assigned fulfillment centers, which is close to mandatory if you import and don't want a garage full of cartons. Price that service per unit and add it to landed cost, because it's a real cost of goods, not an overhead. Once the warehouse receives and scans your units, they show as available and your listings go live for Prime delivery. From that point Amazon may redistribute your stock between its own warehouses without asking you, which is normal, and is also where the counting discrepancies that lead to reimbursement claims tend to begin.

FBA vs. FBM: What's the Difference

FBM (Fulfilled by Merchant) means you store and ship inventory yourself, either from your own warehouse or a third-party 3PL. FBA means Amazon does it. Most established sellers use a mix: high-velocity SKUs in FBA to win Prime badging, slower or oversized items in FBM to avoid storage fees eating margin.

The tradeoff isn't just operational, it's accounting complexity. FBA introduces inventory that lives outside your direct control, gets moved between warehouses, occasionally gets lost or damaged, and generates a fee structure with dozens of line items on every settlement report. FBM keeps fulfillment simpler but shifts more manual work (and shipping cost variability) onto you.

A third model gets compared to both: Amazon FBA vs dropshipping, where you never hold stock at all and a supplier ships each order. Accounting-wise they're barely the same business. Dropshipping has no inventory asset, no storage fees, no lost-unit reimbursements, and no cash locked up months before a sale; FBA has all four, which is why FBA sellers need real inventory accounting and dropshippers often don't. Amazon's own policy on dropshipping is also strict about whose packing slip goes in the box, so read it before building a business on it.

One useful in-between: Amazon's Multi-Channel Fulfillment lets your FBA stock ship orders you took somewhere else, so sellers weighing Amazon vs eBay as channels don't have to split inventory across two fulfillment setups. The fees differ from standard FBA orders and they land in your settlement as their own line type, so map them to a separate expense account rather than burying them with regular fulfillment fees.

Neither model is universally better, and a spreadsheet comparison for your specific catalog beats any general rule. Heavy, cheap, slow-moving items are usually terrible FBA candidates because storage and fulfillment fees scale with size while the sale price doesn't. Small, light, fast-turning products with healthy margins are where FBA shines. Run each SKU through an FBA fee calculator before you commit a purchase order, not after.

• •FBA: Amazon stores, picks, packs, ships, and handles returns
• •FBM: You control fulfillment end-to-end
• •FBA fees: storage + per-unit fulfillment + potential long-term storage surcharges
• •FBM costs: your own warehousing, labor, and outbound shipping

A worked example: what FBA does to unit economics

Numbers make the tradeoff concrete, so here's a fully hypothetical one. Say you sell a kitchen gadget for $30. Your landed cost (factory price plus freight, duties, and prep) is $7 per unit. Amazon takes a referral fee that's a percentage of the sale price, and for a standard-size item like this the combined referral plus FBA fulfillment fee might run in the neighborhood of $10 to $12; the real figure depends on exact dimensions, weight, category, and the current fee schedule, so treat these numbers as illustration only.

On those assumptions, each sale leaves roughly $11 to $13 before storage fees, advertising, and returns. Spend $3 per unit on ads and absorb a 5% return rate and you're closer to $7 per unit of true profit, about a 23% net margin. That's a workable FBA product. Now rerun the same math on a $15 sale price with the same $7 cost and similar fees, and the profit evaporates entirely. This is why experienced sellers screen products on post-fee margin, not on the gap between cost and sale price.

The bookkeeping lesson hidden in the example: five different deductions stood between the $30 sale and your $7 profit, and every one of them arrives as a separate line on your settlement report. If your books only record the net deposit, you can't see which lever (fees, ads, returns, or product cost) is moving your margin.

The Accounting and Tax Side of FBA

FBA doesn't just affect logistics, it changes your books. Inventory sitting in Amazon warehouses still needs to be tracked as an asset, reconciled against what Amazon's reports say is on hand, and adjusted when units go missing, get damaged, or are destroyed. Since 2025, Amazon reimburses lost or damaged FBA inventory based on the seller's manufacturing or sourcing cost rather than retail price. Amazon will estimate that cost unless you've supplied your own, which is a strong reason to keep accurate landed-cost records rather than let Amazon guess.

FBA also puts your inventory physically in multiple states, which historically could create sales tax nexus questions. Thankfully, nearly every state with a sales tax now has a marketplace facilitator law requiring platforms like Amazon to collect and remit sales tax on third-party sales, so Amazon generally handles the collection and remittance for you. That said, this shifted after the landmark South Dakota v. Wayfair Supreme Court decision, which let states require out-of-state sellers to collect tax based on economic nexus rather than physical presence, the ruling that made marketplace facilitator laws possible in the first place.

Taxes for Amazon sellers really split three ways, and mixing them up causes most of the confusion. There's sales tax you charge buyers, which Amazon now collects and remits on marketplace orders in nearly every state; income tax on your profit, which is entirely yours to handle; and sales tax on Amazon purchases you make yourself, which catches arbitrage sellers who buy their inventory retail. If you're buying goods for resale, a resale certificate plus enrollment in Amazon's tax exemption program is what makes those purchases tax exempt. An Amazon Business account is where you set that up, and it's worth doing, since paying sales tax on inventory you're going to resell is money you generally don't get back.

One mechanical detail on the collection side: Amazon assigns each listing a product tax code, and that Amazon tax code determines how the item is taxed by state (clothing, groceries, and supplements are all treated differently in different places). Set it wrong and the tax to be collected on your orders is wrong, which you'll only discover later. Check the code on new listings rather than accepting the default.

On top of that, sellers need to watch the tax forms Amazon issues, mainly the 1099-K. The threshold for when platforms must issue a 1099-K has been in flux rather than fixed, so don't assume last year's rule still applies. Check the current IRS guidance for the applicable threshold before assuming you're under it.

Because FBA generates so many small transactions (fees, reimbursements, refunds, storage charges, advertising costs), reconciling it by hand in a spreadsheet gets unmanageable fast. That's the gap purpose-built ecommerce accounting software is designed to close: matching settlement data to your books line by line instead of lumping everything into one 'Amazon deposit' entry.

Common FBA mistakes new sellers make

Most FBA failures trace back to a handful of repeatable errors, and none of them are about picking the wrong product niche.

Sending too much inventory too soon tops the list. Storage fees reward fast turnover and punish stagnation, so a conservative first shipment that sells through in six to eight weeks beats a container that sits for a year accruing long-term storage surcharges. Second is skipping prep requirements: a shipment rejected or relabeled at the warehouse costs you fees and weeks of lost sales momentum. Third is ignoring reconciliation. Amazon's warehouses handle billions of units, and a small percentage of yours will be lost, damaged, or miscounted; sellers who never audit their inventory reports simply donate that money. An fba reimbursement service or amazon reimbursement software can automate the audit, and even a quarterly manual check of Amazon's inventory adjustment reports beats doing nothing.

The quieter mistake is treating amazon fba accounting as something to sort out later. Landed cost per SKU, settlement-level fee tracking, and an inventory asset account are day-one requirements, not scaling problems. Every downstream number (reimbursement claims, taxable profit, reorder decisions) depends on them, and reconstructing costs a year later from old supplier emails is miserable work.

Next steps: setting up FBA the right way

If you're moving forward with FBA, do these in order. Open a professional seller account, verify the current fee schedule for your category, and run your candidate products through the fee calculator with honest freight and prep numbers. Then set up your accounting stack before the first shipment: a business bank account, a ledger (QuickBooks or Xero are the usual choices), and a landed-cost record per SKU.

On tooling, be honest about your stage. A brand-new seller with one SKU can run amazon bookkeeping in a spreadsheet for a while, and that's fine. Once settlements arrive every two weeks with hundreds of lines, most sellers add amazon accounting software that parses each settlement into revenue, fees, refunds, and reimbursements and posts clean journals to the ledger. Any tool worth paying for handles the Amazon Seller Central integration through Amazon's API rather than asking you to download reports by hand, so the data arrives without you babysitting it. If you'd rather hand the whole thing off, Amazon seller accounting services (bookkeepers who specialize in marketplace clients) will run the month for you, typically on top of the same software stack. BeanHawk does this with reimbursement auditing built in; A2X and Link My Books are established alternatives worth comparing. If inventory planning is your bottleneck rather than the books, amazon inventory management software (or broader amazon seller tools that bundle restock forecasting with fee analytics) solves a different problem, so decide which pain you're actually paying to remove. The best accounting software for amazon sellers is the one that makes your settlement data match your bank deposits without manual work, because that reconciliation is the foundation everything else sits on.