Bookkeeping Basics for E-commerce Founders
Most online sellers only think about bookkeeping when tax season arrives — and by then the numbers are a year-long tangle. Start on day one and it stays simple. Here's the short list of what to track, the one mistake nearly everyone makes with payouts, and the plain-English version of inventory and COGS.
Why bother from day one
Bookkeeping is just the habit of writing down what comes in and what goes out, in a way you can add up later. Started early, it's a few minutes a week and your tax return almost writes itself. Left until the end of the year, it becomes archaeology — digging through a dozen accounts to reconstruct what happened, usually while a deadline looms. The founders who find tax season painless aren't the ones with the biggest businesses; they're the ones who never let the records fall behind. The goal isn't fancy accounting. It's being able to answer, at any moment, "did I actually make money, and can I prove it?"
What to track from day one
You don't need much to start, but you do need it consistently. Capture:
- Sales — what customers actually paid, order by order, not just the lump sum that hits your bank.
- Platform and processor fees — the cut Amazon, Etsy, Shopify, Stripe, or PayPal take before you ever see the money.
- Refunds and returns — money that came in and then went back out.
- Cost of your products — what you paid suppliers for the goods you sell.
- Operating expenses — ads, shipping supplies, software subscriptions, contractors, and the like.
- Sales tax collected — money you gathered on behalf of a state, which was never yours to keep.
Keep the receipts and the platform statements behind these numbers. A record without its backup is just a claim; with the statement attached, it's evidence.
Why a payout is not your revenue
This is the single biggest trap for online sellers, so it's worth being blunt: the amount a marketplace deposits into your bank is not your sales figure. By the time money reaches you, the platform has already subtracted its fees, netted out refunds, sometimes held back a reserve, and may have folded in sales tax it collected. A $10,000 week of sales might land as a $7,400 payout. If you treat that $7,400 as your revenue, every number downstream is wrong; if you treat it as your profit, you'll wildly overstate how well you're doing.
The correct move is to record the gross sale and each deduction separately, so the payout is the result of your books, not the input to them. This is also why a 1099-K — which reports gross payments — never matches your bank deposits, and why your own records are what reconcile the two.
Inventory and COGS, in plain words
Two accounting words scare newcomers more than they should. Inventory is simply the products you've bought but haven't sold yet — stock sitting in a warehouse or a fulfillment center. Here's the part that surprises people: buying inventory is not an expense at the moment you pay for it. You've swapped cash for goods of equal value; you're not poorer, just holding product instead of money.
The cost only becomes an expense when the item sells — and at that point it's called COGS, or "cost of goods sold." So if you buy 100 units at $6 each and sell 30 this month, your COGS this month is $180 (the 30 you sold), and the other $420 stays on the books as inventory until those units move. Getting this right is what separates real profit from a number that just looks like profit. Sell $3,000 of goods that cost you $1,000 and spend $500 on ads, and your actual profit is $1,500 — not the $3,000 that came in, and not the payout that hit your bank.
Keep business and personal apart
From the very first sale, run the business through its own bank account and its own card. Paying for stock from your personal account "just this once" is how books turn into a mess — every mixed transaction is one you'll have to untangle later, and blurring the line can undercut the liability protection your LLC is supposed to give you. A dedicated account isn't bureaucracy; it means your bookkeeping is halfway done before you start, because the account statement is the business's story. For non-resident founders, our guide to opening a US business bank account covers how to get that account in the first place.
When spreadsheets stop working
A spreadsheet is a perfectly good start — for one sales channel and a modest number of orders, it's fine. It starts to buckle when reality gets more moving parts: several channels at once (Amazon plus Shopify plus wholesale), inventory that has to stay in sync across them, sales tax owed in multiple states, or sales in more than one currency. Around that point the manual copying eats more time than it saves and quietly introduces errors. The signal to graduate to proper accounting software — and usually to a bookkeeper — is when you notice you're spending evenings maintaining the spreadsheet instead of running the business, or when you no longer trust the totals. Catching this transition early is far cheaper than reconstructing a year later.
What we handle for you
We set up e-commerce books that treat payouts correctly, track inventory and COGS the right way, and keep sales tax where it belongs — so your profit is a number you can actually trust, month to month. It's the core of our e-commerce & Amazon practice, from solo stores to multichannel brands that need a fractional CFO. When bookkeeping and the wider sales-tax-versus-income-tax picture come together, filing season turns into a formality. Tell us how you sell and we'll get your numbers in order.