Amazon FBA Accounting: Untangling Fees, Payouts & COGS

Why Amazon FBA Accounting Is So Hard

Amazon doesn't hand you clean numbers. What lands in your bank every two weeks is a single net payout — gross sales minus a dozen kinds of fees, refunds, reserves, and adjustments, all blended together. Drop that deposit into "sales" and your revenue is understated, your fees are invisible, and your real margin is anyone's guess. FBA accounting is the work of pulling that settlement apart.

Start With the Settlement, Not the Deposit

The number that matters isn't the deposit — it's the settlement report behind it. Each settlement breaks the payout into its parts: product sales, refunds, FBA fees, referral fees, storage fees, advertising, and reserves held back. Good FBA bookkeeping records the gross sales and each fee category separately, so the deposit is the result of the math, not the math itself.

The FBA Fees You Have to Track

• Referral fees — Amazon's commission on each sale.
• FBA fulfillment fees — pick, pack, and ship.
• Storage fees — monthly and long-term.
• Advertising (PPC) — often your biggest controllable cost.
• Refunds and reimbursements — returns net against sales; reimbursements for lost or damaged inventory are their own line.

Lumped together, these hide which fees are eating your margin. Separated, you can see that storage or ads — not the product — is the real problem.

Get COGS and Inventory Right

Your cost of goods sold only hits the books when a unit sells, not when you buy inventory or ship it to Amazon. Until then it's an asset sitting in a warehouse. FBA sellers who expense inventory at purchase wildly distort monthly profit. Clean books track inventory as an asset and move it to COGS as units sell — which is what makes your margins real.

Don't Forget Reserves and Timing

Amazon holds reserves and pays on its own schedule, so the cash you can see rarely matches the profit you've earned. Accrual-based books — recognizing sales when they happen, not when Amazon pays — give you the honest picture. The reserve is money you've earned but can't touch yet, and the books should show it that way.

Sales Tax and Multi-State Nexus

Storing inventory in Amazon's warehouses can create sales-tax nexus in states you've never visited. Marketplace facilitator laws mean Amazon collects and remits for many of those sales — but you still need to track where you have nexus, especially if you also sell off-Amazon.

The Bottom Line

FBA accounting is settlement accounting: break each payout into gross sales and its fees, track inventory as an asset until it sells, and use accrual to see past Amazon's reserves and timing. Do that, and you finally know your true margin per product instead of guessing from a biweekly deposit.