E-commerce Accounting & Tax Compliance: The Complete Guide

eCommerce accounting operates under different rules than traditional retail. Revenue recognition timing depends on shipping terms and digital delivery. Marketplace fees from Amazon, Shopify, eBay, and Etsy create complex journal entries where gross revenue and net deposits are different numbers. Sales tax compliance spans dozens of jurisdictions with different rules, rates, thresholds, and filing deadlines. International sellers must navigate VAT, GST, customs duties, and digital services taxes across multiple countries. Inventory valuation methods (FIFO, LIFO, weighted average) directly impact profitability calculations and tax obligations. And cost of goods sold includes not just product cost but landed cost — freight, duties, insurance, and handling that many eCommerce businesses fail to capture accurately.

Getting this wrong has real consequences: understated tax liabilities trigger penalties and interest, incorrect revenue recognition misstates financial performance, and inaccurate COGS leads to pricing decisions based on phantom margins. This guide covers every accounting and tax compliance topic that eCommerce businesses face, with practical guidance for implementation.

Key Takeaways

• Record gross revenue, then deduct platform fees, refunds, and discounts as separate line items — never record net deposits as revenue
• US sales tax nexus exists in most states once you exceed $100K sales or 200 transactions — marketplace facilitator laws shift collection responsibility to platforms for marketplace sales
• EU VAT requires IOSS registration for shipments under 150 EUR; OSS for digital services; full VAT registration for warehouse-based selling
• Inventory must be valued consistently (FIFO recommended for most eCommerce) and include landed cost for accurate COGS
• Revenue is recognized at shipment (FOB Shipping Point) or delivery (FOB Destination) for physical goods, and immediately for digital products
• Reconcile at the settlement/payout level — match platform payouts to recorded transactions, not individual orders

---

Revenue Recognition for eCommerce

Revenue recognition by product type:

Gross vs. net revenue recording:

This is the single most common accounting error in eCommerce. When you sell a $100 product on Amazon and receive a $85 deposit (after Amazon's referral fee, FBA fee, and other charges), the temptation is to record $85 as revenue. This is incorrect.

Correct recording:

Why this matters: Gross revenue reflects your true sales volume and is used to calculate marketplace fees as a percentage of revenue, sales tax obligations (based on gross sales, not net), and revenue trends over time. If you record net deposits as revenue, your revenue is understated, your expense ratios are skewed, and sales tax calculations may be incorrect.

Refunds and returns accounting:

When a customer returns a $100 product:

Under ASC 606, you must also estimate expected returns at the time of sale and record a refund liability. Calculate your rolling 90-day return rate and apply it to current-period sales.

---

Marketplace Fee Tracking

Each marketplace has a different fee structure, and tracking these fees accurately is essential for understanding true profitability by channel.

Major marketplace fee structures:

Chart of accounts for marketplace fees:

Create separate expense accounts for each marketplace's fee types:

5100 - Marketplace Fees
  5110 - Amazon Referral Fees
  5120 - Amazon FBA Fees
  5130 - Amazon Storage Fees
  5140 - Amazon Advertising Fees
  5150 - Shopify Payment Processing Fees
  5160 - eBay Final Value Fees
  5170 - Etsy Transaction Fees
  5180 - Etsy Payment Processing Fees

This granularity allows you to analyze profitability by marketplace and fee type — critical for decisions about which platforms to prioritize and which products to sell where.

---

Sales Tax Compliance (United States)

US sales tax is a state-level tax with no federal sales tax. After the Supreme Court's 2018 Wayfair decision, states can require out-of-state sellers to collect sales tax if they exceed economic nexus thresholds in that state.

Economic nexus thresholds (2026):

Most states use a $100,000 gross revenue OR 200 transactions threshold. Some states use only a revenue threshold, and some have lower thresholds.

Marketplace facilitator laws:

In most states, marketplace facilitators (Amazon, eBay, Etsy, Walmart) are required to collect and remit sales tax on sales made through their platform. This means:

• Sales through Amazon, eBay, Etsy: The platform collects and remits sales tax. You do not need to collect or remit for these sales (but you may still need to report them)
• Sales through your own Shopify store: You are responsible for collecting and remitting sales tax in states where you have nexus

Sales tax implementation checklist:

1. Determine nexus — Review revenue and transaction counts by state. Register for sales tax in states where you exceed the threshold
2. Configure collection — Enable tax collection in Shopify (Shopify Tax handles rate calculation), Amazon (already handled by marketplace facilitator), and other channels
3. File returns — File sales tax returns in each registered state on their required schedule (monthly, quarterly, or annually depending on volume)
4. Use automation — Services like TaxJar, Avalara, or Vertex automate rate calculation, return preparation, and filing across all states
5. Review quarterly — As your business grows, you may cross nexus thresholds in new states. Review quarterly and register in new states as needed

---

VAT and International Tax Compliance

EU VAT framework for eCommerce sellers:

UK VAT for eCommerce:

Since Brexit, the UK is a separate VAT jurisdiction:

• All goods shipped to UK consumers from abroad, valued at or under 135 GBP: seller must register for UK VAT and charge VAT at checkout (20% standard rate)
• Goods over 135 GBP: customer pays import VAT at customs
• Marketplace sales: Online marketplaces (Amazon UK, eBay UK) collect and remit VAT on goods shipped from overseas valued at or under 135 GBP

Other international tax obligations:

---

Inventory Valuation and COGS

Inventory valuation directly impacts your cost of goods sold (COGS), gross profit, and tax liability. The method you choose — FIFO, LIFO, or weighted average — must be applied consistently and documented.

Inventory valuation methods compared:

FIFO is recommended for most eCommerce businesses because it matches the physical flow of goods (you ship older inventory first), is accepted under both IFRS and US GAAP (LIFO is prohibited under IFRS), and produces balance sheet inventory values closest to current replacement cost.

Landed cost: The complete picture of COGS

Product cost alone does not represent your true cost of goods. Landed cost includes all costs to get the product to your warehouse, ready for sale:

If you use $10.00 as your COGS instead of $12.50, your gross margin is overstated by 25% — leading to pricing decisions based on phantom profits.

---

Reconciliation Workflows

eCommerce reconciliation is complex because platform payouts bundle multiple transaction types (sales, refunds, fees, adjustments, reserves) into a single deposit.

Payout-level reconciliation process:

1. Receive payout — Amazon/Shopify/eBay deposits funds to your bank account
2. Download settlement report — The platform provides a detailed breakdown of the payout: gross sales, refunds, fees, adjustments, and reserves
3. Match payout to bank deposit — Verify the settlement total matches the bank deposit amount
4. Record journal entries — For each line item in the settlement:
   • Gross sales → Revenue
   • Refunds → Sales Returns and Allowances
   • Platform fees → Marketplace Fees Expense (by type)
   • Adjustments → Other Income/Expense
   • Reserves → Accounts Receivable (held by platform)
5. Reconcile to open orders — Verify that the number and amounts of settled orders match your order management system
6. Investigate discrepancies — Common causes: timing differences (orders placed but not yet settled), chargebacks not yet processed, FX rate differences

Reconciliation frequency recommendations:

For comprehensive eCommerce accounting support — from multi-platform reconciliation and tax compliance to inventory valuation and financial reporting — explore ECOSIRE's accounting service. Our team handles the accounting complexity across Shopify, Amazon, eBay, and other platforms, so you can focus on growing your business.

---

Frequently Asked Questions

Should I record revenue as gross sales or net of marketplace fees?

Always record gross sales as revenue and marketplace fees as a separate expense. This is required under ASC 606 (when you control the goods before transfer to the customer) and provides accurate data for sales tax calculations, revenue trend analysis, and fee ratio monitoring. Recording net deposits as revenue understates your true sales volume and creates compliance issues with sales tax authorities who base obligations on gross sales.

Do I need to collect sales tax on Amazon and eBay sales?

In most US states, no — marketplace facilitator laws require Amazon, eBay, Etsy, and Walmart to collect and remit sales tax on your behalf for sales made through their platforms. However, you may still need to report these sales on your state tax returns (even though the platform remits the tax), and you are responsible for collecting sales tax on sales through your own website (Shopify store, etc.) in states where you have nexus.

What is the difference between IOSS and OSS for EU VAT?

IOSS (Import One-Stop Shop) is for goods shipped from outside the EU to EU consumers, valued at 150 EUR or less. You register once, charge VAT at checkout at the destination country rate, and file a monthly return through your IOSS registration country. OSS (One-Stop Shop) is for goods shipped from within the EU to consumers in other EU member states, or for digital services sold to EU consumers. OSS uses a quarterly filing. Both schemes simplify VAT compliance by avoiding the need to register separately in each EU country.

How do I calculate cost of goods sold for eCommerce?

COGS = Beginning Inventory + Purchases (including landed cost) - Ending Inventory. The critical factor is including all landed costs in your purchase cost: product cost, freight, customs duties, insurance, and handling. Choose an inventory valuation method (FIFO recommended) and apply it consistently. Track inventory using perpetual inventory management (updated in real time with each sale and receipt) rather than periodic counts, which are too infrequent for eCommerce.

How often should I reconcile marketplace payouts?

Monthly for stores processing under 100 orders per month, bi-weekly for 100-1,000 orders, weekly for 1,000-10,000 orders, and daily (with automation) for stores exceeding 10,000 orders per month. The longer you wait between reconciliations, the harder it is to investigate discrepancies because details fade and transaction volume compounds. Real-time or daily reconciliation also gives you accurate cash flow visibility for decision-making.

Do I need separate accounting for each sales channel?

Not separate accounting systems, but separate tracking within your accounting system. Use a channel dimension, class, or department in your chart of accounts to tag revenue and expenses by channel (Amazon, Shopify, eBay, wholesale, etc.). This allows you to produce profit and loss statements per channel to understand which channels are truly profitable after all direct costs (fees, fulfillment, advertising, returns). Most accounting platforms support multi-dimensional reporting for this purpose.

How do I handle chargebacks in eCommerce accounting?

When a chargeback is initiated, record it as: Debit Chargeback Expense or Sales Returns (for the transaction amount) and Credit Cash or Accounts Receivable. If you also lose the chargeback fee, debit Chargeback Fees Expense and credit Cash. If you win the chargeback dispute, reverse the original entries. Chargebacks that cannot be recovered after the dispute period may be classified as bad debt expense. Track chargeback rates by channel and product — a rate above 1% signals a product quality, description accuracy, or fraud issue.