Bookkeeping for E-commerce Sellers: A Complete Beginner's Guide

Why E-commerce Bookkeeping Is Different

If you sell products online, your bookkeeping challenges are fundamentally different from a service-based business. You are dealing with inventory costs, shipping fees, marketplace commissions, payment processor fees, returns, and sales tax across multiple jurisdictions, sometimes all from a single transaction.

A $50 product sold on Amazon might generate a $50 sale, a $7.50 Amazon referral fee, a $3.22 FBA fulfillment fee, a $12 cost of goods, and sales tax obligations in three states. If you do not track all of these components separately, your profit calculations will be wrong.

Setting Up Your Chart of Accounts

Your chart of accounts is the backbone of your bookkeeping system. E-commerce sellers need specific accounts that general business templates do not include.

Essential E-commerce Accounts

Account	Type	What It Tracks
Product Revenue	Income	Gross sales before fees and returns
Marketplace Fees	Expense	Amazon, Etsy, Shopify, eBay commissions
Payment Processing Fees	Expense	Stripe, PayPal, Square transaction fees
Shipping and Fulfillment	Expense	Postage, FBA fees, packaging materials
Cost of Goods Sold	COGS	Purchase price of products sold
Inventory Asset	Asset	Value of unsold products on hand
Returns and Refunds	Contra-revenue	Refunds issued to customers

Tracking Revenue Across Multiple Platforms

Most e-commerce sellers operate on multiple channels. You might sell on Amazon, your own Shopify store, and Etsy simultaneously. Each platform has its own payout schedule, fee structure, and reporting format.

The key is to record gross revenue and fees separately, not just the net deposit you receive. When Amazon deposits $4,200 into your bank account, that is not $4,200 in revenue. It might be $5,100 in sales minus $900 in fees. Recording only the deposit understates your revenue and hides your true fee costs.

Recording a Multi-Platform Sale

For every payout, download the settlement report from the platform. It breaks down gross sales, fees, refunds, and the net deposit. Map each component to the correct account in your chart of accounts.

Key Takeaway: Never book marketplace deposits as straight revenue. Always break them into gross sales, fees, and refunds. This gives you accurate margin data and prevents tax miscalculations.

Managing Cost of Goods Sold

COGS is one of the most important and most frequently miscalculated numbers in e-commerce bookkeeping. Your COGS includes the purchase price of items you sold, plus any costs to get them ready for sale such as shipping to your warehouse, labeling, and packaging.

For inventory accounting, most small e-commerce businesses use one of two methods:

FIFO (First In, First Out): The oldest inventory costs are assigned to sales first. Best for perishable or trending products.
Weighted Average: The average cost of all inventory is used for each sale. Simpler to calculate and suitable for most product types.

For more on tracking COGS in inventory-light models, see our guide on accounting for dropshipping businesses.

Sales Tax for E-commerce

After the 2018 South Dakota v. Wayfair Supreme Court decision, online sellers may have sales tax obligations in every state where they have economic nexus. Economic nexus thresholds vary by state, but a common standard is $100,000 in sales or 200 transactions within a state per year.

Track your sales by state from day one. Many sellers do not realize they have nexus obligations until they are far past the threshold and owe back taxes plus penalties.

Monthly Bookkeeping Routine for E-commerce

Set aside 2 to 3 hours at the end of each month for these essential tasks:

Download settlement reports from every marketplace and payment processor
Reconcile bank deposits against platform payouts
Update inventory values based on purchases and sales
Record COGS for all units sold
Review and categorize all other business expenses

Tools like Finntree automate much of this process by categorizing transactions automatically and flagging discrepancies between your bank data and expected platform deposits.