Most first-time sellers learn ecommerce accounting the expensive way, at tax time, from a CPA's invoice. Here are the answers up front, in plain language, so you set it up right before the mess starts.
Before the questions, internalize this: the money that lands in your bank from a marketplace is not your revenue. It is your sales minus fees, minus advertising, minus refunds, minus whatever the platform held back. Almost every accounting mistake a first-time seller makes traces back to treating that deposit as revenue. Once you separate "what I sold" from "what hit my bank," the rest of ecommerce accounting becomes manageable.
The questions below are the ones first-time sellers actually ask, answered without jargon.
Yes. Amazon, Shopify, and the rest give you dashboards, not books. A dashboard shows sales and some fees; it does not produce a P&L, track inventory as an asset, calculate true cost of goods sold, or give you anything a tax return or a lender will accept. You need real bookkeeping that turns those dashboards into financial statements.
Bookkeeping is the day-to-day recording of transactions: sales, fees, expenses, deposits. Accounting is the layer on top that turns those records into financial statements, tax filings, and decisions. As a first-time seller you mostly need clean bookkeeping; a CPA handles the higher-level accounting and tax work, and they can only do that well if your bookkeeping is solid.
At the very beginning, a spreadsheet can work. It stops working fast. Once you have meaningful inventory and more than a trickle of orders across channels, a spreadsheet cannot reliably apply per-unit cost of goods sold or enforce that your books balance. The signs you have outgrown it are concrete, and the move to real software is more straightforward than it looks. See /blog-posts/migrate-spreadsheets-to-ecommerce-accounting.
Because the marketplace subtracts its cut before paying you: referral fees, fulfillment fees, advertising, refunds, and sometimes a reserve it holds temporarily. A smaller deposit is normal and expected. The deposit tells you how much cash arrived, not how much you sold or earned. Your real numbers come from the settlement report, not the bank line.
Cost of goods sold (COGS) is what the products you actually sold cost you. The stress is justified, because getting it wrong distorts your profit and your taxes. The right way is per unit: each item sold carries its own cost, ideally on a FIFO basis. The wrong way, which many beginners use, is expensing inventory when you buy it, which makes buying months look terrible and selling months look amazing while telling you nothing real about margin.
| APPROACH | WHAT IT DOES | RESULT |
| Expense inventory at purchase | Counts cost when you pay the supplier | Distorts monthly profit |
| Per-unit COGS at sale (FIFO) | Counts cost when the item sells | Accurate margin by SKU |
You take its selling price and subtract everything: the per-unit product cost, the marketplace fees on that sale, the shipping or fulfillment cost, and a fair share of advertising. First-time sellers routinely discover that a product they thought was a winner barely breaks even once fees and ad spend are counted. You cannot see this without per-unit COGS and fees broken out by channel.
Three categories. Income tax on your profit, paid by you, often in quarterly estimates. Sales tax, which you collect from customers and remit to states where you have nexus, though marketplaces remit it on their facilitated sales for you. And, if you pay contractors, 1099-NEC filings. Sales tax money is never yours; you hold it in trust for the state.
It depends on where you have nexus. Marketplaces like Amazon collect and remit sales tax on the sales they facilitate, so you usually do not handle it on those. On your own channels like Shopify, you collect and remit yourself in states where you have nexus, which you acquire through physical presence or by crossing that state's sales threshold. As a first-time seller, register where you have a real obligation and lean on a CPA for the rest.
Once your business is generating real profit and no employer is withholding tax for you, you are generally expected to pay income tax in quarterly installments. Estimate from your accrual profit, not your bank deposits, and set the cash aside as you earn it. A CPA can size your first few payments.
Sooner than most first-time sellers think, and definitely before you are managing inventory across locations and selling on more than one channel by hand. The moment you cannot quickly answer "what did this SKU make" or your month-end takes days, you have outgrown manual methods.
ConnectBooks is built for multi-channel sellers. It syncs Amazon, Shopify, Walmart, eBay, and TikTok Shop into QuickBooks Online, QuickBooks Desktop, or Xero, applies FIFO COGS per unit, tracks inventory across FBA, 3PL, and your warehouse, separates marketplace-facilitator from self-collected sales tax, and produces per-channel P&L. Plans start at $149/mo. Crunch, the AI CFO feature, is in active beta with a waitlist for the full release. See /crunch.
| NEXT STEPSet your books up right from the start. ConnectBooks brings every channel into clean, per-SKU accounting, starting at $149/mo. See /pricing. |
Treating the marketplace deposit as revenue. The deposit is net of fees, advertising, refunds, and reserves, so booking it as sales understates revenue, hides costs, and makes margin impossible to read. Recognize gross sales from the settlement report and record the fees and refunds separately.
For the sales they facilitate, yes. Amazon, Walmart, eBay, and TikTok Shop collect and remit sales tax on their platforms under marketplace facilitator laws. On your own channels like Shopify, you are responsible for collecting and remitting in states where you have nexus. So a seller on both can have tax handled by the marketplace on one side and owed by themselves on the other.
Per unit, with each item carrying its actual cost, ideally on FIFO, recognized when the item sells. Avoid the beginner habit of expensing inventory when you buy it, which scrambles monthly profit. Per-unit COGS is the only way to see accurate margin by product and channel.
For the very earliest stage, a spreadsheet can work. It breaks down quickly once you carry inventory and sell across channels, because it cannot reliably apply per-unit COGS or guarantee your books balance. Plan to move to real software before the manual work and error risk outgrow the savings.
A 1099-K comes to you from marketplaces and processors reporting gross payments they handled; it is informational and you reconcile it to your books. A 1099-NEC is a form you send to contractors you paid $600 or more for services. One you receive, one you issue, and confusing them is a common first-year error.
Clean, accurate books make this manageable. Start a free trial of ConnectBooks to get settlement-level accuracy and real margin visibility for your ecommerce business. No credit card required.
Running an e-commerce business comes with plenty of challenges, but ConnectBooks is here to make your life easier. With real-time insights, seamless integrations, and detailed tracking of your profitability and inventory, you can stay ahead of the game. Whether you’re selling on Amazon, Shopify, Walmart, TikTok or eBay, ConnectBooks helps you manage your finances with 100% accuracy and confidence, so you can focus on growing your business.
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