Ecommerce Bookkeeping: Sales Tax, Inventory & Multi-Channel Sales

Ecommerce looks simple from the outside — sell a product, money lands in the bank — but the bookkeeping is some of the trickiest in small business. A single Shopify or Amazon payout blends sales, shipping, refunds, and fees into one net number, inventory has to be tracked as it moves, and sales tax can apply in dozens of states at once.

This guide breaks down ecommerce bookkeeping — reconciling payouts, inventory and COGS, sales tax nexus, and the tools that make it manageable — whether you’re keeping your own store’s books or serving ecommerce sellers as a bookkeeper.

Why ecommerce bookkeeping is different

• Deposits are net, not gross. Platforms pay you after deducting fees, refunds, and reserves, so the bank deposit never equals your actual sales.
• You sell across channels. Shopify, Amazon, eBay, Etsy, and a website may all feed one business, each with different reporting.
• Inventory drives profit. Cost of goods sold is the biggest expense, and getting it wrong distorts margin completely.
• Sales tax is multi-state. Economic nexus means you can owe tax in states you’ve never set foot in.

Recording sales correctly (the #1 mistake)

The most common ecommerce bookkeeping error is booking the bank deposit as revenue. That single number hides everything that matters.

Instead, record each element separately from the platform’s settlement report:

• Gross sales (the real top line)
• Refunds and returns
• Platform and payment processing fees (Shopify, Amazon, Stripe, PayPal)
• Shipping collected and shipping costs
• Sales tax collected (a liability, not income)

Then reconcile the net of those to the actual deposit. Doing this by hand every payout is painful, which is why most ecommerce bookkeepers use a connector like A2X or Link My Books to post accurate summary entries into QuickBooks Online or Xero.

Inventory and COGS

Inventory is an asset until it sells; only then does its cost become cost of goods sold. Expensing all inventory purchases when you buy them is a common mistake that overstates costs in buying months and understates them in selling months.

To get COGS right:

• Track inventory purchases and units on hand
• Move cost to COGS as units sell (perpetual inventory is ideal)
• Account for shipping-in, duties, and landed cost in the inventory value
• Reconcile inventory value periodically to a physical or system count

For higher-volume sellers, an inventory system (Cin7, DEAR/Cin7 Core, or the platform’s own) feeds the accounting file.

Sales tax nexus and marketplace facilitators

Since the 2018 Wayfair decision, sellers can have economic nexus — an obligation to collect sales tax once they exceed a state’s sales or transaction threshold, even with no physical presence.

Two things to get straight:

• Marketplace facilitator laws — Marketplaces like Amazon, Etsy, and eBay collect and remit sales tax on their platform sales for you. You still report them, but you’re not remitting that tax.
• Your own website — Sales through Shopify or WooCommerce are your responsibility. Track collected tax as a liability and remit per each state’s schedule.

A tool like Avalara or TaxJar helps track nexus and file returns as the seller grows.

Setting up the chart of accounts

An ecommerce chart of accounts separates the moving parts:

• Sales income by channel (Shopify, Amazon, wholesale)
• Contra-revenue accounts for refunds and discounts
• Merchant and platform fees as their own expense
• Cost of goods sold, with inventory as a balance-sheet asset
• Sales tax payable as a liability
• Gift cards and store credit as deferred revenue

Software for ecommerce bookkeeping

• Core ledger: QuickBooks Online or Xero
• Sales connector: A2X or Link My Books to post accurate channel summaries
• Inventory: Cin7 Core, DEAR, or platform inventory
• Sales tax: Avalara or TaxJar
• Receipts/docs: Dext or Hubdoc — see free tools for bookkeepers and accountants for no-cost options

Pricing ecommerce bookkeeping

Ecommerce clients justify higher fees because of channel reconciliation, inventory, and multi-state sales tax. Price on transaction volume, number of sales channels, and whether you handle sales tax filing. See how to price bookkeeping services for benchmarks and package examples.

Frequently asked questions

Why is ecommerce bookkeeping so complicated?

Ecommerce sales flow through platforms and payment processors that deposit net amounts after fees, refunds, and holds, so the deposit on the bank statement rarely matches gross sales. Add inventory and COGS, multi-channel selling, and sales tax across many states, and reconciling accurately takes a dedicated process and usually a connector tool.

How do you record Shopify or Amazon payouts?

You should not book the bank deposit as revenue. A single payout nets sales, shipping, refunds, and platform fees together. The correct approach is to record gross sales, fees, refunds, and taxes separately using a summary from the platform, then reconcile the net to the deposit. Tools like A2X or Link My Books automate this.

Does an ecommerce seller need to collect sales tax in every state?

No. You collect where you have nexus, which can be physical (inventory, office) or economic (exceeding a state’s sales or transaction threshold). Marketplace facilitator laws mean platforms like Amazon collect and remit tax on marketplace sales for you, but sales through your own website are your responsibility.

How is inventory handled in ecommerce bookkeeping?

Inventory is an asset until it sells, at which point its cost moves to cost of goods sold. Accurate COGS requires tracking inventory purchases and units sold, ideally with a perpetual inventory system or an inventory tool that feeds the accounting file, rather than expensing all purchases immediately.

Related guides

• Choosing a profitable accounting firm niche
• How to start a bookkeeping business
• Other industry guides: construction, nonprofit, real estate, restaurant, and law firm bookkeeping.