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Bookkeeping for ecommerce: inventory, COGS and the payout problem

August 7, 2026 · Written by Parag Jain, CPA · 6 min read

Ecommerce books break on three things a service business never meets: inventory as an asset, the gap between a sale and a payout, and sales tax nexus. Here is how to set each one up.

Bookkeeping

Ecommerce bookkeeping goes wrong in a specific and recognisable way. The bank feed shows a deposit from a marketplace, someone categorises it as revenue, and the books are now wrong in three directions at once. Revenue is understated, fees are invisible, and refunds have quietly disappeared.

Three things drive most ecommerce accounting problems and none of them exist in a service business: inventory is an asset rather than an expense, the money that lands in your bank is not your sales figure, and sales tax obligations follow where your customers are rather than where you are.

The payout is not the revenue

A marketplace or payment processor deposits net proceeds. If you sold $10,000, refunded $600, and the platform took $1,000 in fees, roughly $8,400 arrives. Booking $8,400 as revenue records none of the fees, none of the refunds, and a sales figure that is 16% too low.

The correct treatment splits the payout into its components: gross sales, refunds and returns, platform and processing fees, shipping charged to the customer, and sales tax collected, which is not revenue at all but money you are holding on behalf of a state.

This matters beyond tidiness. Fees are one of your largest cost lines and a lever you can negotiate, and you cannot manage a cost you cannot see. Netting them into revenue also inflates gross margin, because the fee never appears in cost of revenue.

Inventory is an asset until it sells

Buying stock is not an expense. It converts cash into a different asset. The expense happens when the item sells, at which point its cost moves to cost of goods sold.

Getting this wrong produces books that swing wildly and mean nothing: a big loss in the month you restock, then an artificially profitable month while you sell it. Neither reflects the business, and the pattern makes forecasting impossible.

EventWhat actually happens
You buy $20,000 of stockCash falls, inventory rises. No expense.
You sell half of itRevenue recorded; $10,000 moves from inventory to COGS
Stock is damaged or obsoleteWritten down as a loss when you know, not when you dispose of it
Stock is in transit or at a fulfilment centreStill your asset if you own it

The last row catches people out. Inventory sitting in a fulfilment warehouse or on a ship is still on your balance sheet, and companies that only count what they can see understate assets and overstate cost.

Sales tax follows your customers

Economic nexus rules mean you can owe sales tax registration and filing in a state you have never been to, triggered by sales volume or transaction count into that state. Thresholds vary by state and change.

Marketplace facilitator laws complicate it in a helpful direction: for sales through large marketplaces, the marketplace often collects and remits on your behalf. That does not automatically remove your registration or filing obligation, and it does not cover your direct channel. The practical consequence is that a business selling on both a marketplace and its own site can have quite different obligations for each.

Zinance tip

Track sales tax collected as a liability from day one, in its own account, separate from revenue. It is not your money. Companies that discover this late find they have been spending it, and the reconstruction is worse than the tax.

Multi-channel is where it compounds

Selling through your own store, a marketplace and a wholesale channel means three different fee structures, three payout schedules and three sets of data, and each channel reports differently.

  • Reconcile per channel, not in aggregate. One combined revenue number hides which channel is actually profitable after fees.
  • Expect payout timing to differ by channel, so cash and revenue diverge in ways that are normal but need explaining.
  • Watch for double counting when an integration and a bank feed both import the same transactions, which is the most common source of inflated revenue.
  • Track fees, shipping and refunds by channel, since channel profitability after those is often very different from what gross sales suggest.

How to set it up

  1. Run accrual accounting. With inventory in the picture, cash-basis actively misleads.
  2. Build a chart of accounts that separates gross sales, refunds, platform fees, processing fees, shipping income and shipping cost.
  3. Reconcile every payout to its underlying settlement report rather than accepting the deposit as a single figure.
  4. Track inventory continuously, including goods in transit and at fulfilment centres.
  5. Hold sales tax collected in its own liability account and reconcile it to what you file.

Where Zinance fits

Zinance handles the reconciliation work that makes ecommerce books usable: payouts split to their components, inventory tracked as an asset, and channel-level margin you can actually act on. Books close daily, so stock and cash decisions are made on current numbers rather than after month end. See our work with e-commerce businesses, and how to structure a chart of accounts for the foundation this depends on.

Disclaimer

This article is educational and general, not tax or accounting advice, and it creates no client relationship. Sales tax nexus thresholds and marketplace facilitator rules vary by state and change. Confirm your own registration and filing obligations with a qualified tax professional.

Two adjacent pieces cover the parts this depends on: how to structure a chart of accounts for the account structure that makes channel margin visible, and the month-end close checklist for the routine that keeps inventory and payouts reconciled.

Frequently asked questions

Why does my bank deposit not match my ecommerce sales?+
Because the deposit is net proceeds. The platform has already deducted its fees and processing costs and netted off refunds, and the deposit may include sales tax collected, which is not revenue. Booking the deposit as revenue understates sales, hides your fees entirely and inflates gross margin. Split each payout into gross sales, refunds, fees, shipping and sales tax.
How should ecommerce businesses account for inventory?+
As an asset until it sells. Buying stock converts cash into inventory rather than creating an expense, and the cost moves to cost of goods sold when the item is sold. Include goods in transit and stock held at fulfilment centres, since you still own them. Expensing purchases directly produces wild monthly swings that make forecasting impossible.
Do I need to worry about sales tax nexus?+
Probably, if you sell into multiple states. Economic nexus rules can create registration and filing obligations based on sales volume or transaction count into a state, with thresholds that vary and change. Marketplace facilitator laws mean large marketplaces often collect and remit for you, but that does not automatically remove your own registration obligation or cover your direct channel.
Should ecommerce use cash or accrual accounting?+
Accrual. With inventory in the business, cash-basis actively misleads: a large restock looks like a catastrophic month and the following month looks unusually profitable, when neither reflects what happened. Accrual matches the cost of goods to the sale that generated the revenue.
How do I handle multiple sales channels?+
Reconcile each channel separately rather than in aggregate, because fee structures and payout timing differ and an aggregate revenue figure hides which channel is actually profitable after fees. Watch for double counting where a platform integration and a bank feed both import the same transactions, which is the most common cause of overstated revenue.

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