E-Commerce Bookkeeping: The Guide Your Online Business Actually Needs

A couple from Midtown walked into our office last spring with a problem they didn’t know they had. Their Etsy shop selling hand-poured candles had crossed $180,000 in annual revenue. Shopify was their second channel. They were profitable — or they thought they were. Then we looked at the numbers and found they owed sales tax in 12 states they’d never registered in, their cost of goods was calculated wrong, and the “profit” in their bank account didn’t account for $23,000 in unreconciled payment processor fees.

Ecommerce bookkeeping breaks people because it looks simple on the surface. Money comes in from Shopify, goes into the bank, and you spend some of it on supplies. Except between the sale and the bank deposit, there are platform fees, payment processing fees, refunds, chargebacks, sales tax collected, shipping costs, and currency conversions — all happening automatically, silently, and in a format that doesn’t match what QuickBooks expects.

This guide covers the pieces that trip up ecommerce sellers the most, starting with the one that can trigger actual legal consequences.

Sales Tax Nexus: The Problem Nobody Sees Coming

If you sell online and ship to customers in other states, you probably have sales tax obligations beyond Texas. The 2018 Supreme Court ruling in South Dakota v. Wayfair changed everything. States can now require out-of-state sellers to collect and remit sales tax once they hit certain thresholds — usually $100,000 in sales or 200 transactions in that state.

Every state sets its own threshold. Some count gross sales. Some count only taxable sales. Some count transactions. The thresholds change. And they’re not uniform.

Here’s what this looks like in practice. That candle company in Midtown was shipping to customers in California, New York, Florida, and about 30 other states. They’d crossed the economic nexus threshold in 12 of them without realizing it. Each of those states expected them to register for a sales tax permit, collect the correct rate on each sale (which varies by county and city), and file returns — some monthly, some quarterly, some annually.

Texas has its own quirks. The state sales tax rate is 6.25%, but local jurisdictions add up to 2%, bringing the combined rate as high as 8.25% in Houston. If you sell from a home office in Sugar Land, your local rate is different from a warehouse in Pearland.

What to do about it:

Track where your customers are. Most ecommerce platforms (Shopify, Amazon, Etsy) provide reports showing sales by state. Use that data to determine where you’ve crossed nexus thresholds. Services like TaxJar, Avalara, or the built-in Shopify Tax tool automate sales tax calculation, collection, and filing. They cost $20-$100+ per month depending on volume, but they’re cheaper than the penalties for non-compliance.

Payment Processor Reconciliation: Where the Numbers Get Weird

Stripe deposits money into your bank account. But the amount deposited doesn’t match the amount sold. Stripe takes its 2.9% + $0.30 per transaction before depositing. If a customer pays $50, Stripe deposits $47.25. Multiply that across hundreds of transactions with refunds, chargebacks, and partial payments mixed in, and you get a bank statement that looks nothing like your sales report.

Shopify Payments works the same way — fees deducted before deposit. Amazon is worse because they hold funds, deduct multiple fee types (referral fees, FBA fees, storage fees, advertising costs), and deposit on their own schedule.

The bookkeeping challenge is recording the full sale amount as revenue, the fees as expenses, and reconciling against what actually landed in the bank. Most ecommerce sellers either record the bank deposit as revenue (understating sales and hiding fees) or record the gross sale and never account for the fees (overstating profit).

Neither is right.

The correct approach:

Record the gross sale amount as revenue. Record each fee type as a separate expense category — payment processing fees, platform fees, marketplace referral fees. Then reconcile the net deposit against the bank statement. This is tedious if you do it manually, which is why accounting integrations (A2X, Link My Books, Synder) exist specifically to bridge the gap between ecommerce platforms and accounting software.

We set up A2X for about half of our ecommerce clients. It pulls Shopify, Amazon, or Etsy transactions and creates summarized journal entries in QuickBooks that match the actual bank deposits. Monthly reconciliation goes from a four-hour headache to a 20-minute review.

Inventory Accounting: FIFO, Weighted Average, and Why It Matters

If you sell physical products, inventory accounting determines your cost of goods sold (COGS), which determines your gross profit, which determines your tax bill. Get it wrong and you either overpay taxes or undercount expenses — both of which cause problems when the numbers get big enough.

FIFO (First In, First Out) assumes you sell the oldest inventory first. If you bought 100 candles at $3 each in January and 100 more at $4 each in March, the first 100 you sell carry a $3 cost. This method works well when your costs are rising — it shows higher profit now but reflects reality if you’re actually shipping older stock first.

Weighted Average blends the cost of all units. Those 200 candles have an average cost of $3.50 each. Simpler to calculate, smoother numbers, less volatile COGS month to month.

For most small ecommerce businesses, FIFO is the standard and what the IRS expects unless you’ve elected a different method. Whatever you choose, be consistent. Switching methods year to year raises flags.

The real inventory problem for ecommerce sellers isn’t the accounting method — it’s tracking inventory at all. Sellers on multiple platforms need to reconcile physical inventory against what Shopify says is in stock, what Amazon FBA says is in the warehouse, and what’s actually sitting in the garage in Katy. Discrepancies between platforms and physical counts create phantom inventory that throws off COGS and financial statements.

Returns and Refunds: The Silent Profit Killer

Returns are a cost center that ecommerce sellers chronically underestimate. A product sells for $50. The customer returns it. You refund $50 but you’ve already paid $1.75 in payment processing fees that Stripe doesn’t return. You paid $8 in shipping to send it. The return shipping cost you $6. The item can’t be resold at full price.

That “free return” cost your business $15.75 plus the margin loss on the returned product. At a 15% return rate (common in apparel and accessories), returns can eat 3-5% of gross revenue before you even notice.

Bookkeeping for returns means recording the refund as a reduction in revenue (not an expense), writing off non-refundable fees, and adjusting inventory back in. If returned products are damaged or unsellable, they go to inventory write-offs — a separate expense category.

Track your return rate by product and by platform. Amazon’s return rate is typically higher than direct Shopify sales because Amazon makes returns frictionless for buyers. That’s important data when deciding where to focus your selling efforts.

Chart of Accounts for Ecommerce (What Actually Works)

A standard small business chart of accounts doesn’t fit ecommerce well. Here’s what we set up for our online sellers:

Revenue accounts:

• Product Sales (broken out by platform if volume warrants it)
• Shipping Revenue (if you charge for shipping)

COGS accounts:

• Product Costs / Materials
• Packaging and Shipping Supplies
• Inbound Freight
• Platform Referral Fees (Amazon, Etsy marketplace fees)

Expense accounts:

• Payment Processing Fees (Stripe, Shopify Payments, PayPal)
• Platform Subscription Fees (Shopify monthly, Amazon seller account)
• Advertising (broken out by platform — Google Ads, Meta Ads, Amazon PPC)
• Shipping Costs (outbound)
• Return Shipping
• Inventory Write-Offs
• Sales Tax Automation Software
• Warehousing / Storage (including Amazon FBA fees)

The goal is visibility. When a client asks “am I actually making money on Amazon versus Shopify?” these categories give us the answer in five minutes instead of a day-long forensic accounting exercise.

Cash vs. Accrual: Which Method for Ecommerce

Most ecommerce businesses start with cash basis accounting because it’s simpler. Revenue is recorded when the money hits your bank account. Expenses are recorded when paid.

The problem with cash basis for ecommerce: timing distortions. Amazon might hold two weeks of sales and deposit them all at once. Your December sales show up as January revenue. Q4 holiday inventory purchases might hit in October but the sales don’t happen until November and December. Cash basis makes your monthly financials unreliable for decision-making.

Accrual basis records revenue when earned (at the time of sale) and expenses when incurred (when you receive inventory, not when you pay for it). It gives a more accurate picture of profitability by period. The IRS requires accrual basis if your business has inventory and gross receipts exceed $29 million, but most small ecommerce businesses fall well below that threshold and can choose either method.

Our recommendation for ecommerce sellers doing over $100,000 in annual revenue: switch to accrual. The monthly financials become useful for actual decision-making. Below that, cash basis is fine as long as you understand its limitations.

The Monthly Bookkeeping Routine That Keeps Ecommerce Sellers Sane

Weekly (15 minutes):

• Review bank feed in QuickBooks for uncategorized transactions
• Check that platform payouts match expected amounts

Monthly (1-2 hours, or outsource to us):

• Reconcile each sales platform against bank deposits
• Reconcile payment processor fees against fee reports
• Record inventory purchases and update COGS
• Review and categorize all business expenses
• Run a P&L and compare to prior month
• Check sales tax liability by state

Quarterly:

• Physical inventory count (compare against platform records)
• Estimated tax payment calculation and filing
• Sales tax filing for applicable states
• Profitability review by product and platform

Annually:

• Full year reconciliation
• Tax preparation (Schedule C for sole props, Form 1065 or 1120S for partnerships and S-Corps)
• Inventory valuation for year-end
• Review and adjust chart of accounts if business model has changed

When DIY Stops Working

Most ecommerce sellers start doing their own books. For the first $50,000-$100,000 in revenue, that’s reasonable. A QuickBooks subscription, an ecommerce integration tool, and a few hours a month keep things manageable.

Past $100,000, the complexity increases faster than most sellers expect. Multi-state sales tax obligations multiply. Inventory accounting gets more involved. Advertising spend across multiple platforms needs tracking and ROI analysis. And the cost of getting something wrong — a missed nexus registration, an incorrect COGS calculation, a tax filing error — goes up with the numbers.

That Midtown candle couple? They spent about $8,000 in back taxes, penalties, and registration fees cleaning up their multi-state sales tax mess. Monthly bookkeeping from the start would have caught the nexus issue when they crossed the first threshold. The ongoing cost of professional ecommerce bookkeeping is almost always less than the cost of fixing the mistakes that pile up without it.