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Economic Nexus Explained: When Do You Owe Sales Tax in a State You've Never Visited?

Taxero Team·9 min read

Economic Nexus Explained: When Do You Owe Sales Tax in a State You've Never Visited?

Last updated: April 2026 | Reading time: ~9 minutes

The short answer: You can owe sales tax in a state you've never visited, have no office in, and have never shipped from — if your sales into that state exceed its economic nexus threshold. The standard threshold is $100,000 in sales OR 200 transactions in a calendar year. Once crossed, you must register, collect, and remit sales tax.

This concept — called economic nexus — changed everything about online selling when the Supreme Court established it in 2018. If you sell online and you're not tracking your sales by state, you probably have compliance gaps you don't know about.

Here's everything you need to understand.

The Case That Changed Everything: South Dakota v. Wayfair (2018)

Before June 2018, online sellers only owed sales tax in states where they had physical presence — a store, warehouse, office, or employees. If you were a one-person operation shipping from your garage in Ohio, you didn't owe sales tax to California just because a California customer bought from you.

Then the Supreme Court ruled in South Dakota v. Wayfair, Inc. (585 U.S. ___, 2018) that physical presence is not required for a state to impose sales tax obligations on a seller.

South Dakota had passed a law requiring out-of-state sellers to collect sales tax once they either:

  • Made $100,000 in sales into South Dakota, OR
  • Completed 200 or more transactions into South Dakota

The court upheld this law. The ruling opened the door for every state to establish similar economic nexus thresholds — and they all did, within about two years.

The result: If you sell online, you potentially owe sales tax in every state where you make significant sales. Not just your home state. Every state.

The Standard Economic Nexus Threshold

The standard threshold that most states adopted mirrors South Dakota's original law:

$100,000 in total sales into the state in a calendar year OR 200 or more transactions into the state in a calendar year

Either condition — hitting the dollar amount OR the transaction count — typically triggers nexus. You don't need to hit both.

This threshold applies in the majority of U.S. states. But "majority" doesn't mean all — and the exceptions matter.

State-by-State Variations You Need to Know

States with Higher Dollar Thresholds

Alabama — $250,000 in sales Alabama uses a Simplified Sellers Use Tax (SSUT) program with an 8% flat rate. It's a simplified system designed for small sellers. Threshold: $250,000 in annual sales. No transaction count component.

Mississippi — $250,000 in sales Mississippi's threshold is $250,000 in sales, no transaction component. Lower-volume sellers may be below this threshold even with significant transaction counts.

Oklahoma — $100,000 in sales only Oklahoma uses only the dollar threshold, with no 200-transaction alternative. You must hit $100,000 in Oklahoma sales to trigger nexus.

States That Eliminated the Transaction Count Threshold

Several states that originally had both a dollar and transaction threshold have since removed the 200-transaction prong, leaving only the $100,000 threshold:

  • Massachusetts — removed the 100-transaction threshold in 2023
  • California — $500,000 in sales (California's threshold is much higher)
  • New York — $500,000 in sales AND 100 transactions (both must be met)
  • Texas — $500,000 in sales only

California and New York are notable for having higher thresholds. Many smaller sellers who've crossed the standard $100K threshold in other states are still below California's $500,000 mark.

Illinois: The Marketplace Facilitator Exception

Illinois has a unique wrinkle worth understanding. Illinois enacted a "Leveling the Playing Field" law that treats marketplace-facilitated sales differently from direct sales for nexus determination. If you sell exclusively through marketplace facilitators (like Amazon, Etsy, eBay, etc.) and have no direct sales into Illinois, you may not trigger nexus — even if your total Illinois sales exceed $100,000. This is a state-specific exception, not the norm. Direct sales into Illinois count toward the standard threshold.

For current Illinois rules, see the Illinois Department of Revenue's remote seller guidance.

States with No Sales Tax

These states have no sales tax and therefore no nexus obligations:

  • Oregon
  • Montana
  • New Hampshire
  • Delaware
  • Alaska (no statewide tax, but the ARSSTC coordinates local taxes)

Rolling Year vs. Calendar Year Lookback

When you count your sales toward a state's economic nexus threshold, the lookback period matters significantly.

Calendar Year: Most states measure nexus on a calendar year basis — January 1 through December 31. If you cross $100,000 on October 15, you have nexus for the rest of that year and need to register.

Rolling 12 Months: Some states use a rolling 12-month window — they look at the previous 12 months from any given date. This means you could trigger nexus mid-year based on sales that started partway through the prior year.

States using rolling 12-month lookback include:

  • California (12-month rolling)
  • Pennsylvania (12-month rolling)
  • Several others

Why this matters: Calendar-year sellers sometimes think they're safe because they only hit $80K so far "this year" — but if they did $30K in November–December of last year, a rolling lookback might put them at $110K.

Check each state's DOR website for its specific lookback period. Many state DOR sites have updated guidance for remote sellers. See the Streamlined Sales Tax Governing Board for centralized information across SST member states.

What Counts Toward the Threshold

Not every dollar you touch counts the same way. Here's what generally counts:

Usually counted:

  • Gross sales of taxable goods
  • Gross sales of exempt goods (in most states, total sales before exemptions)
  • Marketplace-facilitated sales (in most states)
  • Your own direct/website sales

Often excluded or handled differently:

  • Sales tax itself (the tax collected on top of the purchase price)
  • Freight and shipping (varies by state)
  • Returns and refunds (typically reduce your total)

Marketplace-facilitated sales and thresholds: In most states, your total gross sales through a marketplace facilitator count toward your nexus threshold — even though the marketplace collects the tax. This is one of the most confusing aspects of post-Wayfair compliance.

Example: If you sell $90,000 on eBay and $15,000 through your own website in Texas, you've crossed Texas's $500,000... wait, no, you're at $105,000 total Texas sales, which is below Texas's $500,000 threshold. But if that happened in a state with a $100,000 threshold, you'd have nexus.

What Triggers the Registration Obligation

Economic nexus triggers a registration obligation — meaning you must:

  1. Register with the state's Department of Revenue to get a sales tax permit
  2. Collect the appropriate sales tax on sales to that state's residents
  3. File returns on the schedule the state assigns you (monthly, quarterly, or annually)
  4. Remit the tax collected to the state

The obligation starts when you cross the threshold. In most states, you should register before you make your first post-threshold sale. In practice, some sellers register at the start of the following month or quarter after crossing. Don't wait too long — each unregistered sale after the threshold is a potential liability.

Nexus Ends When Sales Drop Below the Threshold — Usually

If your sales into a state drop below the threshold and stay there, you may eventually lose nexus — but it's not automatic. Most states require that you formally deregister and may require that you maintain registration for a period after dropping below the threshold.

Don't just stop filing if you think you no longer have nexus. Contact the state DOR to deregister properly.

How to Track Economic Nexus Across States

Manual tracking is painful but doable if you're on one or two platforms. Here's the approach:

  1. Pull gross sales by state from every platform (Amazon Seller Central, Etsy shop manager, eBay, TikTok Shop, etc.)
  2. Sum all sales by state on a monthly basis
  3. Track running totals for each state against that state's threshold
  4. Flag states approaching 80% of threshold — that's your early warning

Alternatively: use Taxero to connect all your platforms and get automatic nexus tracking with alerts when you're approaching a threshold. That's literally what we're built for.

Step-by-Step: What to Do Once You Have Nexus

1. Confirm the threshold has been met

Pull your data. Make sure you've actually crossed the threshold (right lookback period, right transaction type counting).

2. Register in the state

Options:

3. Configure tax collection

For each sales channel, configure it to collect sales tax from buyers in the state. Most platforms (Amazon, Etsy, Shopify) have tax settings where you can enable collection by state.

4. Determine your filing frequency

When you register, the state will assign you a filing frequency. Expect:

  • Monthly if you have high sales volume in the state
  • Quarterly for moderate volume
  • Annual for low volume

5. File on time

Even if you collected $0 in tax (because a marketplace collected it all), some states require a "zero return." Check requirements when you register. Missing a filing — even for $0 — can trigger notices and penalties.

How Taxero Automates This

Economic nexus tracking across 45 states is exactly the kind of problem that destroys hours every month when done manually — and creates real liability when done wrong.

Taxero:

  • Aggregates your sales across all platforms into a unified state-by-state view
  • Tracks your threshold progress in real time with threshold alerts
  • Tells you when you need to register before it becomes a compliance emergency
  • Files your returns automatically in every state where you have an obligation

$49.99/month (Managed) or $19.99 per filing (Self-Serve). No spreadsheets. No panic.

Start your free nexus assessment at taxero.ai →

Frequently Asked Questions

Q: What is economic nexus in simple terms? A: Economic nexus means you owe sales tax in a state based on your sales volume there — not whether you have a physical presence. If you sell more than $100,000 (or in some states $500,000) in goods to customers in a state, that state can require you to register and collect sales tax, even if you've never set foot there.

Q: Does the $100,000 threshold apply in every state? A: No. The $100,000 threshold is the most common, but exceptions exist. California and New York have $500,000 thresholds. Alabama and Mississippi use $250,000. A few states don't count transactions at all, only dollar amounts. Always check the specific state's DOR for current rules.

Q: Do marketplace-facilitated sales count toward my nexus threshold? A: In most states, yes. Your total gross sales into a state — including sales through Amazon, Etsy, eBay, TikTok Shop, and Whatnot — count toward the threshold. The marketplace may collect the tax, but the sales still count for nexus purposes. Check your state-by-state rules, as a few states (notably Illinois) handle this differently.

Q: When exactly do I need to register after crossing a threshold? A: Most states expect registration before making the first sale that crosses the threshold or shortly after crossing it. In practice, register at the start of the month following the month you crossed the threshold. Don't delay more than a quarter — the longer you wait, the larger the uncollected liability.

Q: I crossed the threshold in one year. Does that mean I have nexus forever? A: Not forever. But nexus doesn't end automatically when your sales drop. Most states require you to maintain registration for the remainder of the year you registered and often the next full year. After that, if you're consistently below threshold, you can deregister. Contact the state DOR to deregister — don't just stop filing.

Q: What's the difference between economic nexus and physical nexus? A: Physical nexus is created by physical presence — a warehouse, office, employees, or inventory in a state. Economic nexus is created by sales volume alone. You can have physical nexus without economic nexus (a small pop-up store in a state with no sales) or economic nexus without physical nexus (selling $200,000 online to customers in a state you've never visited). Both types of nexus obligate you to collect and remit sales tax.

Q: Do I owe back taxes for years before I knew I had nexus? A: Possibly, yes. States can assess tax from the date you exceeded their threshold. The lookback period varies, but it's often 3 years under a Voluntary Disclosure Agreement (VDA) or potentially longer under audit. If you have historical exposure, contact a CPA or consider a VDA program through the Multistate Tax Commission to resolve past liability with reduced penalties.

Primary Sources

This post is for informational purposes only and does not constitute tax advice. Consult a licensed CPA or sales tax attorney for advice specific to your situation. Nexus thresholds and state rules change frequently; always verify with the relevant state Department of Revenue.

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