E-commerce Sales Tax: Nexus and What Shopify Sellers Need to Know
Since the Wayfair ruling, you don't need a physical office to owe sales tax. Economic Nexus can trigger tax registration in 40+ states.
If you sell products online — whether through your own Shopify store, Amazon, Etsy, or any other channel — sales tax is your responsibility. This guide explains economic nexus, marketplace facilitator rules, and how to stay compliant without over-registering.
Key Takeaways
- The Threshold: Usually $100,000 in sales OR 200 transactions into a specific state.
- The Risk: If you cross the line and don't collect, YOU owe the tax (plus penalty/interest).
- Marketplace Facilitators: Amazon/Etsy/eBay collect for you. Shopify does NOT (automatically). You must configure it.
- Registration: Do not register just to be safe. Register only when you hit the threshold. Filing 50 zero-returns is a nightmare.
The Wayfair Decision: Why This Matters
Before 2018, you only owed sales tax in states where you had a physical presence — an office, warehouse, or employee. In June 2018, the Supreme Court ruled in South Dakota v. Wayfair, Inc. that states can require remote sellers to collect sales tax based on economic activity alone. This was a seismic shift for e-commerce.
The ruling upheld South Dakota’s threshold: $100,000 in sales or 200 transactions into the state. Most states adopted similar thresholds, though the specifics vary.
Economic Nexus Thresholds: State Examples
Most states use the $100,000 / 200 transaction model, but there are important differences.
| State | Threshold | Notes |
|---|---|---|
| California | $500,000 in sales | No transaction count test — higher dollar threshold |
| Texas | $500,000 in sales | No transaction count test |
| New York | $500,000 in sales AND 100 transactions | Must meet BOTH tests |
| Florida | $100,000 in sales | No transaction count test |
| Pennsylvania | $100,000 in sales | No transaction count test |
| South Dakota | $100,000 in sales OR 200 transactions | The original Wayfair standard |
Five states have no sales tax at all: Alaska (no statewide tax, but some localities collect), Delaware, Montana, New Hampshire, and Oregon. If all your customers are in these states, you have no sales tax obligation.
Key detail: thresholds are measured per state, per year. You track each state independently.
Marketplace Facilitator Rules
A “marketplace facilitator” is a platform that hosts third-party sellers and handles the transaction. Under marketplace facilitator laws (now active in 45+ states), the platform is responsible for collecting and remitting sales tax — not you.
What this means for you:
- Amazon, Etsy, eBay, Walmart Marketplace: These platforms collect and remit sales tax on your behalf in all states that require it. You do not need to register separately for sales made through these channels.
- Shopify, WooCommerce, BigCommerce: These are not marketplace facilitators. They are e-commerce platforms that power your own store. You are the seller, and you are responsible for collecting, reporting, and remitting sales tax yourself.
If you sell on both Amazon (where tax is handled) and your own Shopify site (where it is not), you need to track and collect on the Shopify sales independently.
Tools of the Trade
If you sell on your own site (Shopify/WooCommerce), you need software.
- Sales Tax Settings: Turn on “Automatic Tax Calculation” in your platform settings.
- Monitoring: Use a tool like TaxJar or Avalara to track your sales vs. state thresholds. These tools alert you when you approach nexus in a new state.
- Filing: Once registered, you file monthly or quarterly depending on the state and your volume.
Pro Tip: If you have inventory in an Amazon FBA warehouse, that creates Physical Nexus. You owe tax there immediately, regardless of the $100k threshold. Amazon FBA distributes inventory across multiple warehouses — check which states your products are stored in.
Beyond Sales Tax: Income Tax for E-commerce
Sales tax is just one obligation. Your e-commerce profits also face income tax:
- Entity Structure: The right business structure affects how your profits are taxed at the federal level.
- State Income Tax: If you have employees, inventory, or large sales in multiple states, review the state income tax guide to avoid unexpected filing obligations.
- Quarterly Payments: If you are profitable, you need to make quarterly estimated tax payments to avoid underpayment penalties.
- Self-Employment Tax: As a seller, you likely owe self-employment tax on top of income tax.
- Home Office: If you run your business from home, the home office deduction can offset some of your overhead.
Related Guides
- Sales tax calculator to sanity-check rates when you test a new state.
- Small business tax deductions to offset profit while you scale.
- S-corp tax strategies if you’re optimizing payroll vs. distributions once sales stabilize.
- Best accounting software strategic review for cleaner books before multi-state filings.
How sharper.tax Helps
sharper.tax focuses on your federal income tax optimization, but we identify whether your e-commerce business structure is costing you more than it should. We flag S-Corp election opportunities, missed deductions, and retirement account strategies that reduce your overall tax burden. Sophisticated tax planning used to require a high-end CPA — we make it available for free.
Sources
- South Dakota v. Wayfair, Inc. (585 U.S. 162)
- IRS: State Government Websites - Sales Tax
- Streamlined Sales Tax Governing Board: State Information
- Sales Tax Institute: Economic Nexus State Guide
The information above is educational and not tax advice.